First checklist of lichens and lichenicolous fungi from Mauritius, with phylogenetic analyses and descriptions of new taxa

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1 Plant and Fungal Systematics 65(1): 13 75, 2020 DOI: ISSN (print) ISSN (online) First checklist of lichens and lichenicolous fungi from Mauritius, with phylogenetic analyses and descriptions of new taxa Paul Diederich 1 & Damien Ertz 2,3 Article info Received: 29 Sept Revision received: 11 Mar Accepted: 16 Mar Published: 2 Jun Associate Editor Nicolas Magain Abstract. A first checklist of the lichens and lichenicolous fungi from the Republic of Mauritius is presented. It is based on older literature reports and on collections made by the authors, mainly in 2016, from the isles of Mauritius and Rodrigues. A total of 216 species are accepted, either as relevant specimens have recently been critically studied or revised by lichen taxonomists, or as we have collected and identified such material ourselves. A further 226 taxa have been reported from Mauritius but are not accepted here, either as no relevant herbarium material has recently been examined, or as previous records are dubious or erroneous; 111 taxa have been newly described from Mauritius in the past, plus 12 of which the Mauritian origin is dubious. Here we report 56 taxa as new for the island of Mauritius, and we describe two new genera (Baidera, Serusiauxia) and eight new species (Baidera mauritiana, Biatoropsis millanesiana, Chapsa alletii, Collemopsidium mauritiae, Nyungwea pyneei, Porina florensii, Pyrenula muriciliata, Serusiauxia inexpectata). Two new combinations are proposed: Loekoesia apostatica ( Lecanora apostatica) and Sticta flavireagens ( Stictina flavireagens). Phylogenetic analyses are presented for species of Arthoniales, Biatoropsis, Porinaceae, Pyrenulaceae and Teloschistales. Key words: Arthoniales, Biatoropsis, Indian Ocean, Porinaceae, Pyrenulaceae, Rodrigues, Teloschistales Introduction The Republic of Mauritius lies in the southwestern Indian Ocean about 900 km east of Madagascar and about 2000 km off the southeast coast of the African continent. It consists of two main volcanic islands belonging to the Mascarene Archipelago: Mauritius, with a land area of 1865 km² (highest point Piton de la Petite Rivière Noire, 828 m); and Rodrigues, which is the smallest (109 km²; highest point Mt Limon, 398 m) and most isolated of the Mascarene Islands, being located about 574 km east of Mauritius. Basaltic lava is the main type of rock on both islands, but Rodrigues also has areas of limestone made of consolidated coral sands. Mauritius and Rodrigues are the two oldest main islands of the Mascarenes, having been available for colonization by diverse biota for 8 15 million years (Thébaud et al. 2009). The coastal areas of both islands have a dry tropical climate contrasting 1 Musée national d histoire naturelle, 25 rue Munster, L-2160 Luxembourg, Luxembourg 2 Meise Botanic Garden, Department of Research, Nieuwelaan 38, B-1860 Meise, Belgium 3 Fédération Wallonie-Bruxelles, Service général de l Enseignement non obligatoire et de la Recherche scientifique, rue A. Lavallée 1, B-1080 Bruxelles, Belgium Corresponding author paul.diederich@education.lu with the more humid upper elevation, which receives the highest amount of rainfall. Fog is abundant at the upper altitudes and provides the optimum climate for the development of rich macrolichen communities (Figs 1 2). The Mascarene Islands harbour a very rich and diverse angiosperm flora, with an estimated ~960 native species, about 75% of them considered to be endemic to the archipelago (Thébaud et al. 2009). The level of island endemism is also high, being 39.5% in Mauritius (273 single island endemics of the 691 native species) and 31.1% in Rodrigues (47 single-island endemics of the 150 native species) (Baider et al. 2010). The archipelago is even part of the world s most important biodiversity hotspots (Myers et al. 2000). The pristine fauna and flora of the Mascarenes have been decimated since humans arrived in The dodo (Raphus cucullatus), a flightless bird belonging to the Columbidae and endemic to Mauritius, is the emblematic representative of them (Cheke & Hume 2008). Although native vegetation remains, all the pristine forest covering Rodrigues has been destroyed, while barely 2% of the original forest cover has been left in Mauritius, mainly lowland rainforests and dense cloud forests at the highest elevation. They are concentrated in Black River Gorges National Park in the southwest, 2020 W. Szafer Institute of Botany, Polish Academy of Sciences. This is an Open Access article distributed under the terms of the Creative Commons Attribution License CC BY 4.0 (

2 14 Plant and Fungal Systematics 65(1): 13 75, 2020 the Bambou Mountain Range in the southeast, and the Moka Port Louis Ranges in the northwest, with some isolated mountains such as Corps de Garde, Le Morne Brabant, and several offshore islets. These forest remnants are often invaded by alien animals (e.g., deer, mongooses, monkeys, pigs, rats) and plant species (e.g., Psidium cattleianum, Ardisia crenata, Ligustrum robustum, Rubus alceifolius, Wikstroemia indica) (Thébaud et al. 2009, Virah-Sawmy et al. 2009), which have a strong negative impact on biodiversity. Considerable efforts are deployed for conservation management work to fight alien species and restore original forests. The lichen flora of Mauritius and Rodrigues is poorly known and has never been thoroughly revised. This paper aims to provide a first checklist for the lichens and lichenicolous fungi of Mauritius and Rodrigues, along with new records and descriptions of new species resulting from our recent collecting trips. Material and methods Preparation of the checklist and morphological examination The checklist includes both data found in the literature and new results based on our collections. The entire literature for Mauritius has been checked, and all previously published reports of Mauritian lichens have been included in the checklist. Species printed in bold are accepted; these usually represent species either recently studied and published by taxonomists or examined by us. Other species are considered dubious, especially those from the older literature, as no specimens exist or as they have never been critically revised. We have not examined most historical specimens, except for those indicated by an exclamation mark (!). Specimens we collected, mainly in 2016, are retained in MAU (Mauritius Herbarium), while duplicates are kept in BR (Damien Ertz) and in the private herbarium of P. Diederich. A few additional specimens from BM and MAU have been studied. Hand-made sections of ascomata and thalli were studied in water, 5% KOH (K), Lugol s reagent (1% I 2 ) without (I) or with KOH pre-treatment (K/I), lactophenol-cotton blue (LCB), Congo Red or phloxine B. Macroscopic photographs were made using a Canon 40D camera with a Canon MP-E 65 mm lens or a Nikon BD Plan 10 microscope objective, StackShot (Cognisys) and Helicon Focus (HeliconSoft) for increasing the depth of field; or with a Keyence VHX-5000 digital microscope and a VH-Z20R/W/T lens (Baidera, Nyungwea, Serusiauxia). Microscopic photographs were prepared using a Leica DMLB microscope with interference contrast, fitted with a Leica EC3 camera; or an Olympus BX51 microscope with interference contrast, connected to an Olympus Color View I digital camera (Baidera, Nyungwea, Serusiauxia). Chemical spot reactions are abbreviated as K (5% KOH), C (commercial bleach), KC (K followed by C) and PD (paraphenylenediamine), while UV refers to fluorescence at 366 nm. Thin-layer chromatography followed Elix (2014). Ascospores measurements of Baidera mauritiana, Porina florensii and Pyrenula muriciliata are given as (min. )average minus standard deviation average plus standard deviation( max.). Molecular techniques Well-preserved and freshly collected specimens were used for sequencing. A group of 4 to 6 soredia (Serusiauxia) or tiny fragments of the hymenium or thallus (Baidera mauritiana, Granulopyrenis sp., Loekoesia apostatica, Nyungwea pyneei, Porina florensii, Pyrenula quassiicola, Squamulea cf. squamosa) were used for direct PCR as described in Ertz et al. (2015). For Biatoropsis millanesiana, total DNA was extracted directly from the specimens examined (Table 1) using the Qiagen DNeasy Plant MiniKit according to the manufacturer s instructions, but using 50 μl of water in each of the last two steps of final elution. A targeted fragment of ~0.8 kb of the mitochondrial ribosomal RNA small subunit (mtssu) was amplified for Granulopyrenis, Loekoesia, Porina, Pyrenula and Squamulea using primers mrssu1 and mrssu3r (Zoller et al. 1999), and a fragment of ~1 kb of the RPB2 protein-coding gene was amplified for Baidera and Nyungwea using primers frpb2-7cf and frpb2-11ar (Liu et al. 1999). Amplification reactions were prepared for a 50 µl final volume containing the lichen material as explained in Ertz et al. (2018b). The yield of the PCRs was verified by running the products on a 1% agarose gel using ethidium bromide. Both strands were sequenced by Macrogen using amplification primers. Sequence fragments were assembled with Sequencher v. 5.3 (Gene Codes Corporation, Ann Arbor, Michigan). For Biatoropsis millanesiana, we amplified nuc rdna internal transcribed spacer 1 (ITS1), 5.8S, internal transcribed spacer 2 (ITS2) and a fragment of ~0 bp in the rdna 28S region with primers ITS1F (Gardes & Bruns 1993), BasidLSU3-3 (Millanes et al. 2011), BasidLSU1-3 (Millanes et al. 2011), BasidLSU1-5 (Millanes et al. 2011), BasidLSU13-5 (Millanes et al. 2011) and LR5 (Vilgalys & Hester 1990). PCR amplifications were performed using Illustra Hot Start PCR beads according to the manufacturer s instructions, with the primer combinations and settings described in Millanes et al. (2011). Sequencing followed Millanes et al. (2016). Taxon selection and phylogenetic analyses Ten new mtssu sequences were obtained for this study: one for Granulopyrenis (MN for Ertz 21425), one for Loekoesia apostatica (MN for Diederich 18518), two for Porina florensii (MN for Diederich 18348, MN for Diederich 18453), one for Pyrenula quassiicola (MN for Ertz 21460), four for Serusiauxia inexpectata (MN for Diederich 17815, MN for Diederich 18239, MN for Ertz 21490, MN for Ertz 21496) and one for Squamulea cf. squamosa (MN for Diederich 18394). Three new RPB2 sequences were obtained for the Arthoniales: two for Baidera mauritiana (MN for Ertz hymenium, MN for Ertz thallus) and one for Nyungwea pyneei (MN for Ertz 21450).

3 P. Diederich & D. Ertz: First checklist of lichens and lichenicolous fungi from Mauritius 15 Figure 1. Mauritian landscapes and lichen habitats. A Black River Gorges Natural Park with natural forest; B dense natural forest in Brise Fer with the endemic Mauritian ebony tree, Diospyros tesselaria; C typical coastal landscape of Mauritius; D Curepipe Botanic Gardens, an extraordinary habitat for corticolous lichens; E palm tree in Curepipe Botanic Gardens, covered by Usnea and Parmotrema species; F Pétrin heathland, with a rich terricolous and corticolous lichen flora; G Cladonia confusa in Pétrin heathland. Photos: P. Diederich.

4 16 Plant and Fungal Systematics 65(1): 13 75, 2020 Figure 2. Mauritian landscapes and lichen habitats (continued). A rocky boulder in Ebony Forest, Chamarel; B historic cemetery in La Preneuse near Tamarin with a rich flora of Lichinaceae, Collemopsidium mauritiae sp. nov., Endocarpon spp., Squamulea cf. squamosa, etc.; C typical landscape on the east coast of Rodrigues island, with a rocky outcrop on the top of a hill and sparse lowland vegetation with Pandanus, Acacia and Casuarina; D Grande Montagne Nature Reserve in Rodrigues; E Pandanus trees in Rodrigues, with a particularly diverse corticolous lichen vegetation. Photos: P. Diederich (A B, E), D. Ertz (C D).

5 P. Diederich & D. Ertz: First checklist of lichens and lichenicolous fungi from Mauritius 17 Table 1. Voucher information and GenBank accession numbers (NCBI) for ITS and nulsu sequences of Tremellales used in this study. Newly generated sequences are in bold. Type specimens are indicated by (T). Taxon name DNA extraction number Specimen data ITS nlsu Biatoropsis hafellneri AM299 Azores, Diederich 17087b (S F264687) KJ KJ Biatoropsis hafellneri AA10 (T) UK, Wedin 7308 (UPS F holotype) JN JN Biatoropsis millanesiana sp. nov. AM784 (T) Mauritius, Diederich (MAU holotype) MN MN Biatoropsis millanesiana sp. nov. AM1171 Mauritius, Diederich (MAU topotype) MN MN Biatoropsis millanesiana sp. nov. AM1026 Mauritius, Diederich (MAU) MN MN Biatoropsis millanesiana sp. nov. AM1168 Rodrigues, Diederich (MAU) MN MN Biatoropsis millanesiana sp. nov. AM1169 Rodrigues, Diederich (MAU) MN MN Biatoropsis millanesiana sp. nov. AM1170 Rodrigues, Diederich (MAU) MN MN Biatoropsis millanesiana sp. nov. AM567 Seychelles, Diederich (SEY) KX MN Biatoropsis minuta AM172 Canada, Diederich (S F102406) KJ KJ Biatoropsis minuta AM229 India, Divakar s.n. (MAF-Lich) KJ KJ Biatoropsis minuta AM137 (T) Spain, Aragón s.n. (S F holotype) KJ KJ Biatoropsis minuta CO294 Sweden, Wedin 7903 (S F102401) JN JN Biatoropsis protousneae AM215 Argentina, Wedin 8601 (S F264822) KJ KJ Biatoropsis protousneae AM214 Argentina, Wedin 8615 (S F264823) KJ KJ Biatoropsis protousneae AM141 Chile, Pérez-Ortega 216 (MAF-Lich) KJ KJ Biatoropsis protousneae AM142 (T) Chile, Pérez-Ortega 207 (MAF-Lich isotype) KJ KJ Biatoropsis usnearum AM196 Austria, Hafellner (GZU 02-99) KJ KJ Biatoropsis usnearum AM298 Azores, Diederich 17087a (S F264684) KJ KJ Biatoropsis usnearum AM202 Sweden, Westberg (S F264681) KJ KJ Biatoropsis usnearum AM171 UK, Coppins s.n. (S F102407) KJ KJ Biatoropsis sp. A1 AM112 Canary Islands, Diederich (S F102402) KJ KJ Biatoropsis sp. A1 AM192 Chile, Etayo (MAF-Lich 15645) KJ KJ Biatoropsis sp. A1 AM296 New Zealand, Wedin 9033 (S F180874) KJ KJ Biatoropsis sp. A1 AM143 Spain, Pérez-Ortega s.n. (MAF-Lich) KJ KJ Biatoropsis sp. E AM213 Argentina, Wedin 8742 (S F264824) KJ KJ Biatoropsis sp. F AM576 France, Diederich (herb. Diederich) KX MN Biatoropsis sp. F AM10 New Zealand, Berger (S F92784) KJ KJ Biatoropsis sp. F AM1040 New Zealand, Berger (herb. Berger) MN MN Biatoropsis sp. F AM295 New Zealand, Wedin 9429 (S F181399) KJ KJ Biatoropsis sp. F AM166 USA, Kocourková s.n. (S F264679) KJ KJ Tremella cetrariicola AM111 Finland, Suija s.n. (S F102413) JN JN Five new nuits or 28S rdna sequences were obtained for Biatoropsis millanesiana (Table 1). Their closest relatives based on megablast searches were retrieved from GenBank. The phylogenetic trees of Ertz et al. (2019) and Gueidan et al. (2016) were used for the placement of the newly sequenced taxa of Porinaceae and Pyrenulaceae respectively. Additional members of the Arthoniales were selected for the placement of Baidera mauritiana and Nyungwea pyneei from Ertz & Tehler (2011), Ertz et al. (2015) and Frisch et al. (2014), and additional species of Teloschistales were selected for the placement of Loekoesia apostatica and Squamulea cf. squamosa, mainly from Arup et al. (2013). In addition to 24 Biatoropsis specimens representing all known species in the genus and the seven clades studied in Millanes et al. (2014, 2016), seven additional specimens from the Indian Ocean were included in the molecular study (Table 1). Sequences of Arthoniales, Porinaceae, Pyrenulaceae and Teloschistales were aligned using MAFFT v7.402 (Katoh et al. 2002) on the CIPRES Web Portal (Miller et al. 2010) and improved manually using Mesquite 3.04 (Maddison & Maddison 2015). Terminal ends of sequences and ambiguously aligned regions were delimited manually and excluded from the datasets. Sequences of Biatoropsis were aligned using the Q-INS-i algorithm (Katoh & Toh 2008) of the multiple sequence alignment software MAFFT version 7 (Katoh & Toh 2008; Katoh et al. 2017). Two data matrices were produced: one including ITS and one including 28S rdna. Ambiguous regions were identified and eliminated with Gblocks version 0.91b (Castresana 2000). Bayesian analyses were carried out on the Arthoniales, Porinaceae, Pyrenulaceae and Teloschistales datasets using the Metropolis-coupled Markov chain Monte Carlo (MCMCMC) method in MrBayes v (Huelsenbeck & Ronquist 2001; Ronquist & Huelsenbeck 2003) on the CIPRES Web Portal (Miller et al. 2010). Best-fit evolutionary models were estimated using the Akaike information criterion (AIC; Akaike 1973) as implemented in jmodeltest (Darriba et al. 2012). The GTR+I+G model was selected for the Porinaceae dataset, the TIM2+I+G model for the Pyrenulaceae dataset, the HKY+I+G model for the Teloschistales dataset, the GTR+I+G model for both the RPB21st and RPB22nd positions for the Arthoniales dataset, and the TIM2+I+G model for the RPB23rd position for the Arthoniales dataset. For each dataset, two parallel MCMCMC runs were performed, each using four independent chains and

6 18 Plant and Fungal Systematics 65(1): 13 75, million generations, sampling trees every 0 th generation. Tracer v. 1.6 (Rambaut & Drummond 2007) was used to ensure that stationarity was reached by plotting the log-likelihood values of the sample points against generation time, making sure that the ESS values were higher than 200. Convergence between runs was also verified using the PSRF (potential scale reduction factor), where all values were equal or close to Posterior probabilities (PP) were determined by calculating a majority-rule consensus tree generated from the post-burn-in trees of the trees sampled by the two MCMCMC runs using the sumt option of MrBayes for the four datasets. In addition, a maximum likelihood (ML) analysis was performed on the CIPRES Web Portal (Miller et al. 2010) using RAxML-HPC2 v (Stamatakis 2014) with 0 ML bootstrap iterations (ML-BS) and the GTRGAMMA model. The RAxML trees did not contradict the Bayesian trees topology for the strongly supported branches. Therefore, only the RAxML trees are shown, with the bootstrap support values added above or near the internal branches (Figs 4, 10, 13, 16). ML-BS 70 and PP 95 were considered significant. Internal branches considered strongly supported by both the RAxML and Bayesian analyses are represented by thicker lines (Figs 4, 10, 13, 16). Phylogenetic trees were visualized using FigTree v (Rambaut 2012). For the Biatoropsis datasets, maximum likelihood analyses were performed in RAxMLGUI 1.5 (Silvestro & Michalak 2012), a graphical front-end for RAxML (Stamatakis 2014), using the GTRGAMMAI model of nucleotide substitution applied to all partitions. We performed a thorough ML search with 10 runs and assessed node support by thorough bootstrapping using 0 bootstrap pseudoreplicates. The Lichenological Exploration of Mauritius In addition to literature references cited below, the historical data are based partly on valuable information obtained from Wikipedia (de.wikipedia.org, en.wikipedia.org and fr.wikipedia.org). Mauritius The first person to collect lichens in Mauritius seems to have been Philibert Commerson ( ), a French physician, naturalist and explorer. During his circumnavigation with Bougainville in , he reached Mauritius on 8 November While Bougainville left Mauritius one month later, Commerson stayed there and enjoyed excellent working conditions at the botanical garden in Pamplemousses. He also explored Madagascar and Reunion, but returned to Mauritius in February 1771, where he died unexpectedly in His important collections were later brought back to Paris, but it seems that most have not yet been studied. Bory de Saint-Vincent (1828) published the new Roccella flaccida (a synonym of R. boryi), based on a Mauritius specimen obtained in 1826 from A. L. de Jussieu and collected by P. Commerson; Tehler & Irestedt (2007) lectotypified R. flaccida on specimen Jussieu 2444 (PC). Louis-Marie Aubert du Petit-Thouars ( ) was a French botanist who visited Mauritius in He collected many plants and described numerous new orchids from Mauritius, Reunion and Madagascar. In 1801, he guided a botanical excursion with Bory de Saint-Vincent (see below). He returned to France in 1802, bringing with him a herbarium of 2000 plant specimens. Although he did not intentionally collect lichens, the type specimen of the foliicolous lichen Strigula elegans (a synonym of S. smaragdula) kept in G (G ) was collected by him in insula Franciae, supra folia arborum. Jean Baptiste Bory de Saint-Vincent ( ) was a French naturalist who joined an expedition to Australia organized by Captain Nicolas Baudin in However, in March 1801 he left the vessel at Mauritius and spent two years exploring Reunion and other isles in the Indian Ocean. In 1804 he published the results from his expedition in the book Voyage dans les quatre principales isles des mers d Afrique, fait par ordre du Gouvernement, pendant les années neuf et dix de la République (1801 et 1802), avec l histoire de la traversée du capitaine Baudin jusqu au Port-Louis de l Ile Maurice. When he arrived in Port-Louis, he met French botanist Louis-Marie Aubert du Petit-Thouars (see above), who accompanied him during an excursion. In May 1801, he explored the Plaines Wilhems and especially the Corps de Garde (729 m high) in the Moka Range (a mountain range forming a semicircle around the capital, Port Louis). There he collected cryptogams, especially a beautiful golden undescribed Usnea species that he previously had discovered in Brittany (Bory 1804: 197). Then he visited Le Pouce (812 m), also in the Moka Range, where he found a remarkable vegetation. In June 1801, he visited the jardin d Etat aux Pamplemousses, then the forests in the southern part of Mauritius, including the Piton. On 11 August 1801, he left Mauritius for Reunion. Although Bory reported many lichen species from Reunion (Bory 1804), including a number of new species, it seems that he did not publish any of his lichen specimens from Mauritius. Several specimens he collected in Mauritius have been located, such as the lectotype of Sticta dichotoma and the lectotype of S. mougeotiana (both kept in PC Thuret), a specimen later identified by Hue as Stictina carpoloma (PC ), or a specimen collected in 1802 (surely a lapsus for 1801, see above) sur les grands arbres on Le Pouce (PC ). Other specimens from Bory are annotated Iles de France et Bourbon, such as the lectotype of Sticta aurigera var. nuda (PC-Thuret), and some of these might originate from Mauritius as well. In his Histoire des lichens. Genre Sticta, annotated 1822 but published only in 1825, dedicated au Colonel Bory de Saint Vincent, Delise (1825) studied the rich collections made by Bory in the African isles. In his Essai sur les cryptogames des écorces exotiques officinales, Fée (1824: CI) cited Delise, Monog. ined., cum icon., following which the new Roccella boryi Habitat in insula Borboniae, Mauritii, etc., ad rupes ; Tehler & Irestedt (2007) eventually lectotypified that name on a specimen from Ile de Bourbon (Reunion); although no collector

7 P. Diederich & D. Ertz: First checklist of lichens and lichenicolous fungi from Mauritius 19 was mentioned, this certainly refers to specimens collected by Bory. Bohemian botanist Franz Wilhelm Sieber ( ) collected plants in Europe, the Middle East, Southern Africa and Australia. During his circumnavigation, he visited South Africa, Mauritius and Australia. He also sent Bohemian botanist Wenceslas Bojer ( ) to Mauritius in to collect plants for him. After 1820, Sieber s behaviour and publications became progressively more erratic, and he spent the final fourteen years of his life in the Prague insane asylum, where he died at the age of fifty-five. Annotations on his herbarium labels are unreliable, and it seems that at least part of his lichen specimens annotated Mauritius originate from other countries (see below under Cora gyrolophia and Sticta flavireagens). Laurer s (1827) Sieber sche Lichenen reports on collections obtained from Sieber after his circumnavigation. About 25 specimens collected by W. Bojer in Mauritius, two of them dated 1836 and 1838, are now kept in MAU. French botanist Charles-Paulus Bélanger ( ) travelled to the Indes Orientales (Southeast Asia) and incompletely published the results in his work Voyages aux Indes orientales par le nord de l Europe, les provinces du Caucase, la Géorgie, l Arménie et la Perse, suivi de détails topographiques et autres sur le Pégou, les îles de Java, de Maurice et de Bourbon, sur le Cap de Bonne-Espérance et Sainte-Hélène, pendant les années 1825, 1826, 1827, 1828 et Most lichen specimens collected in Mauritius and published by Bélanger (1834) are kept in PC in the Montagne herbarium. A duplicate of the type of Oxystoma friesianum, collected in Pamplemousses, is also kept in G. British physician and botanist Philip Burnard Ayres ( ) was appointed to Mauritius in 1856, where he assembled extensive plant collections. He did not publish on lichens, but collected at least 25, amongst them the type specimens of Cladonia intermediella, Ocellularia mauritiana, Opegrapha angulosa, Pannaria macrocarpa, Pyrenula truncata and Toninia ayresiana. Most specimens are kept in BM, E, G or K. Many originate from Le Pouce, and some are annotated Mauritian naturalist (Jean Marie Rose) Albert Daruty de Grandpré ( ) collected over 150 lichen specimens in , almost all kept in MAU. Daruty (1873) published over 80 species, unfortunately without any indications of locality or ecology, all identified by H. A. Weddell; eight new species, published without descriptions and without type citations, are nomina nuda. Two specimens are also kept in PC (Stictina argyracea, PC ; S. rigidula, PC ). Mauritian physician and naturalist Victor de Robillard ( ) collected about 50 lichen specimens in Mauritius, mainly in 1876, including the types of Pertusaria pertusa var. minor, P. pertusella, P. subtruncata, Stictina robillardii, Synechoblastus robillardii and Usnea straminea. In a small report on the flora of Round Island (Johnston 1894), Henry Halcro Johnston ( ) collected lichens that were later identified by C. H. Wright from the Kew herbarium; he also collected the type of Endocarpon johnstonii on Ile aux Fouquets. The Mauritius Herbarium (MAU) currently houses about 860 Mauritian lichen specimens from many collectors (Baider, pers. comm.), the most important ones, in addition to A. Daruty, being British botanist Reginald Edward Vaughan ( ) (almost 200 specimens collected in ), American botanist David H. Lorence (131 specimens collected in and 1994) and British botanist Colville Barclay ( ) (69 specimens collected in ). Jonathan D. Sauer ( ) collected about 20 lichens in the Macchabee Forest and Pétrin between 1959 and 1961, now kept in MAU, S and WIS. Lars Arvidsson & Dan Nilsson collected lichens in Mauritius in April 1979 (specimens kept in GB); results, mainly on Coccocarpia, have been published by Arvidsson (1982) and Galloway & Jørgensen (1987). Austrian botanists Harald Riedl and Christa Riedl- Dorn visited Mauritius in 1981, with the aim of sampling the entire lichen flora from that country. Their specimens are kept in W, but most seem not to have been identified. Nothing has been published by them, except for a summary of their results (Riedl & Riedl-Dorn 1986), mentioning the genera encountered, not the species. The number of cryptogamic specimens collected is about 500, the majority of them lichens (Riedl & Riedl-Dorn 1986). British mycologist and lichenologist David Leslie Hawksworth collected 83 lichen specimens in 1990, all kept in K-IMI. In a first paper by David & Hawksworth (1995), the authors published, in addition to new records of a number of species, five species new to science: Cladonia mauritiana, Mycomicrothelia leuckertii, Ocellularia petrinensis, Pertusaria hymenelioides and Pertusaria muricata. They announced that the second part would deal mainly with crustose species, but that part was never published. Norwegian lichenologists Hildur Krog ( ) and Einar Timdal visited Mauritius in 1991 and collected about 1150 lichen specimens, all kept in O, with some duplicates in MAU. Some of their results were published by Timdal (2002: new genus and species Krogia coralloides) and Timdal & Krog (2001: 11 species of Phyllopsora reported from Mauritius, including the new P. dolichospora and P. swinscowii with type localities in Mauritius). During a Study Tour to the Mascarenes in 2001, Ulrik Søchting and his students visited Perrier, the Magenta Valley, Le Pétrin, Île aux Aigrettes and Le Pouce in Mauritius. They collected around specimens, kept at C, and some results based on their collections were published in Arup et al. (2013), Johannson et al. (2005), Lücking et al. (2017a), Moncada et al. (2014) and Stenroos et al. (2006). An unpublished report on the Lobariaceae was prepared by students Holm & Gregersen (2002), and a poster presented at IMC 7 in Oslo (Holm et al. 2002). Anders Tehler visited Mauritius in December 2003 with the main aim of collecting Arthoniales, now kept in S; results were published in Tehler & Irestedt (2007) and Tehler et al. (2010, 2013).

8 20 Plant and Fungal Systematics 65(1): 13 75, 2020 Emmanuël Sérusiaux briefly visited Mauritius in 2013 and collected in the Botanical Garden of Pamplemousses and in the forests around Pétrin and the Piton de la Petite Rivière Noire, the specimens being kept at LG; his Sticta specimens have been studied by Simon (2015) and Simon et al. (2018). The second author of this paper, Damien Ertz, briefly visited Mauritius in 2014 and 2016 and collected about 80 lichen specimens in the Botanical Garden in Pamplemousses; those specimens are kept in BR, including the type of the new Glomerulophoron mauritiae, while duplicates of all specimens have been deposited in MAU. The first author, Paul Diederich, visited Mauritius in 2016 and collected about 375 lichen specimens; they will be kept in MAU, with duplicates in the private collection of the author. Both of us also visited Mauritius in August September 2019 and collected about 670 (PD) (DE) specimens, but only a small part of these results are included in the present paper. Rodrigues Scottish botanist Isaac Bayley Balfour ( ) participated in the Venus-Transit Expedition to Rodrigues, where he investigated the local flora from September to December The lichens he collected were studied by James Mascall Morrison Crombie ( ) and William Nylander ( ), and published in three papers. Following an anonymous note at org/stable/ /al.ap.specimen.h , the paper in The Journal of Botany 14: , including short diagnoses of new species, was published in September or October 1876 (Crombie 1876a), while the paper in Journal of the Linnean Society, Botany 15: with longer descriptions and discussions, although Read June 15, 1876, was published only in December 1876 (Crombie 1876b). Crombie (1876a: 262) wrote that he publishes here short diagnoses previous to a more detailed report, confirming that the Crombie (1876a) paper was intended to be published first. A third paper, published in Philosophical transactions of the Royal Society of London 168: (Crombie 1879), represents a copy of Crombie (1876b) and therefore has not been considered in our checklist. In Crombie (1876a), short diagnoses of 26 new species and one new variety were given. Crombie (1876b) gave detailed descriptions of these 27 taxa and also reported many other taxa collected in Rodrigues. This paper additionally described new infra-specific taxa not included in Crombie (1876a), such as Ramalina gracilenta f. nodulosa. Crombie (1876a) described some new species himself, such as Cladonia balfourii Cromb., but attributed others to Nylander, such as Usnea dasypogoides Nyl.. Although Crombie (1876b: 432) acknowledged Nylander who has also kindly sent me his MS. diagnoses of the species determined by him, he failed to do so in his first paper (Crombie 1876a). Therefore the author citation for such species should be Nyl. ex Cromb. or simply Cromb., and not Nyl. (ICN, Art. 46.5, 46.8). Both of us visited Rodrigues in September 2019 and collected about 200 (PD) (DE) specimens, but only a few of these specimens are included here. Other Isles In addition to the isles of Mauritius and Rodrigues, the Republic of Mauritius also comprises the outer islands of Agaléga and St. Brandon; no lichens have yet been reported from these isles, although two Ramalina specimens from Agaléga are kept in MAU. Mauritius further claims sovereignty over the uninhabited isle of Tromelin, from where no lichens have ever been reported, and the Chagos Archipelago, including Diego Garcia. The lichens from the latter archipelago were sampled by Mark Seaward during the 1996 Chagos Expedition and published in Seaward & Aptroot (2000). These records have not been included in our checklist below. The Checklist The checklist is presented in alphabetical order; accepted taxa are in boldface, while dubious taxa and synonyms are not bolded and are in smaller characters; genera are accepted when they include at least one accepted species; species are accepted when representative specimens have been examined either by us or recently by lichen taxonomists; all other reported species for which a re-examination of relevant material is needed are considered dubious. Names of taxa newly described from Mauritius (except those described in this paper) are preceded by an asterisk; when the Mauritian origin of a type is dubious, the asterisk is parenthesised ( ). Names of lichenicolous species (except the one newly described) are preceded by a plus sign. For taxa described from Mauritius, information on types is given, as far as possible, often using online databases, such as JSTOR ( for species known from Mauritius, the frequency and distribution data are often completed using unpublished information from online databases of herbaria, such as the Oslo herbarium (O) ( search?country=mu&dataset_key= c a29- a670-ed1015b26252); however, with a few exceptions, no attempts have been made to re-examine such types or other historical specimens reported from the country. As a rule, specimens collected by the first author are kept in MAU, with duplicates in herb. Diederich; those collected by the second author are kept in MAU, with duplicates in BR; when a single herbarium is indicated, such as (MAU), then there are no further duplicates; Diederich (dupl. LG) means that a duplicate is kept in LG, in addition to duplicates in MAU and herb. Diederich. Taxonomic (heterotypic) synonyms are indicated by =, nomenclatural (homotypic) synonyms by. ACROCORDIA A. Massal. gemmata (Ach.) A. Massal. [ Verrucaria gemmata (Ach.) Ach.]. The report by Daruty (1873) from Mauritius is very doubtful, as this is a temperate species unlikely to occur in the tropics.

9 P. Diederich & D. Ertz: First checklist of lichens and lichenicolous fungi from Mauritius 21 AGONIMIA Zahlbr. opuntiella (Buschardt & Poelt) Vězda Pamplemousses: 1 km NNW of Botanical Garden, S of Museum Aventure du sucre, on bark, 2016, Diederich (MAU). Rivière Noire: Ebony Forest, viewpoint, on exposed rocks, 2019, Diederich pacifica (H. Harada) Diederich Plaines Wilhems: Curepipe, Trou aux Cerfs, along road surrounding the crater, on bark, 2016, Diederich (MAU, sub Thecaria quassiicola). Rivière Noire: Trail from Plaine Champagne towards Piton de la Petite Rivière Noire, on bark, 2016, Diederich (MAU); Ebony Forest, around viewpoint, on bark, 2019, Diederich Savanne: Along trail to Mt Cocotte, on bark, 2019, Diederich & Ertz ALLOGRAPHA Chevall. angustata (Eschw.) Lücking & Kalb [ Graphis angustata Eschw.]. Reported from Mauritius by Daruty (1873). calcea (Fée) Lücking & Kalb Plaines Wilhems: Le Pétrin, between Pétrin Information Centre and first viewpoint along trail to the west, on bark, 2016, Diederich A pantropical species, new for Africa. comma (Ach.) Lücking & Kalb [ Graphis comma (Ach.) Spreng.]. Reported from Mauritius by Daruty (1873). laubertiana (Fée) Lücking & Kalb [ Opegrapha laubertiana (Fée)Bél.]. Sur l écorce des arbres, à l île Maurice (Bélanger 1834). rimulosa (Mont.) Lücking & Kalb Pamplemousses: Jardin Botanique, on bark of Agathis robusta, 2016, Ertz Savanne: Road from Le Pétrin to Chamouny, beginning of trail to Montagne Cocotte, on branches, 2016, Diederich A pantropical species, new for Africa. rustica (Kremp.) Lücking & Kalb = Graphis turgidula Müll. Arg., J. Linn. Soc., Bot. 30: 457 (1895). Type: Mauritius, summit of Mt Pouce, corticolous, Ayres (BM, lectotype; G , G , isolectotypes) (Archer 2006: 83, Archer 2009: 141, Wirth & Hale 1978: 24). Port Louis and Moka: Along trail from Moka to Le Pouce, on bark, 2019, Ertz (TLC: stictic, hypostictic, unknown terpenoid, solvent A). striatula (Ach.) Lücking & Kalb Pamplemousses: Jardin Botanique, on bark, 2016, Diederich (TLC: no substance detected, solvent A). AMANDINEA M. Choisy ex Scheid. & M. Mayrhofer efflorescens (Müll. Arg.) Marbach Moka: Réduit, close to Mauritius Herbarium building, on bark of Mangifera, 2019, Diederich & Ertz Rivière Noire: E of Flic-en-Flac, Casela Nature Park, on bark, 2016, Diederich 18315; La Preneuse (between Tamarin and Grande Rivière Noire), cemetery, on bark at the base of a tree, 2016, Diederich 18387; Le Morne Peninsula, S coast, on bark of Casuarina, 2019, Diederich ANAPTYCHIA Körb. cinerascens (Nyl.) Dodge var. pulvinigera (Müll. Arg.) Dodge. Reported from Rodrigues, 1874, Balfour, by Dodge (1971: 212). comosa (Eschw.) A. Massal. Heterodermia comosa leucomelaena (L.) A. Massal. Leucodermia leucomelos speciosa (Wulfen) A. Massal. Heterodermia speciosa ANISOMERIDIUM (Müll. Arg.) Choisy anisolobum (Nyl.) Aptroot Rivière Noire: Chamarel, Ebony Forest, close to park buildings, on bark, 2016, Diederich 18536; east of Black River, from Visitor s Centre to Pilgrims Trail, on bark, 2016, Diederich ANTHRACOTHECIUM Hampe ex A. Massal. borbonicum (Nyl.) Müll. Arg. = Anthracothecium prasinum denudatum (Nyl.) Müll. Arg. [ Verrucaria denudata Nyl.]. Reported from Mauritius by Daruty (1873), and from Rodrigues, on bark of trees, 1874, Balfour 2244, by Crombie (1876b). prasinum (Eschw.) R. C. Harris [= A. borbonicum (Nyl.) Müll. Arg.]. Reported from Mauritius by Dodge (1964: 17). ARTHONIA Ach. atra (Pers.) A. Schneid. [ Opegrapha atra Pers.]. Sur les bois morts, dans les forêts de l Ile-de-France (Bélanger 1834, as O. atra var. abbreviata Flörke). dendritella Nyl. ex Cromb., J. Bot. 14: 264 (1876). Type: Rodrigues, on thin bark of trees, 1874, Balfour, 2300 (BM, H) (Crombie 1876a, b). obscura Ach. Sur l écorce des arbres, aux îles Maurice et de Bourbon, et dans la péninsule indienne (Bélanger 1834). phylloica Nyl. ex Cromb., J. Bot. 14: 264 (1876). Type: Rodrigues, foliicole (Crombie 1876a) or on thin stems (Crombie 1876b), 1874, Balfour 2226 (BM, H) (Crombie 1876a, b). spectabilis Flot. Arthothelium spectabile ulcerosula Wedd. ex Nyl., Bull. Soc. linn. Normandie, sér. 2, 7: 174 (1874 [ 1873 ]); Arthonia ulcerulosa Wedd., in Daruty, Trans. Roy. Soc. Arts Mauritius, n.s. 7: 163 (1873), nom. nud. Type: Corticola in insula Mauritii. ARTHOPYRENIA A. Massal. quinqueseptatula (Nyl. ex Cromb.) Zahlbr., Cat. Lich. Univ. 1: 335 (1922); Verrucaria quinqueseptatula Nyl. ex Cromb. [as Verrucaria 5-septatula], J. Bot. 14: 265 (1876). Type: Rodrigues, on the thin epidermis of bark of trees, 1874, Balfour 2352 (BM, H) (Crombie 1876a, b).

10 22 Plant and Fungal Systematics 65(1): 13 75, 2020 ARTHOTHELIUM (Vain.) Zahlbr. spectabile A. Massal. [ Arthonia spectabilis (A. Massal.) Anzi]. The report from Mauritius by Daruty (1873) is very doubtful, as this is a temperate species. ASTROTHELIUM Eschw. phlyctaenum (Fée) Aptroot & Lücking [= Verrucaria macrozoma Fée]. Sur l écorce des arbres, dans les forêts du Carnatic et de l île Maurice (Bélanger 1834). Verrucaria macrozoma is a synonym of Trypethelium catervarium (Fée) Tuck. (fide Awasthi 1965), of which the current name is Astrothelium phlyctaenum (fide Aptroot et al. 2016: 997). BACIDINA Vězda medialis (Nyl.) Kistenich, Timdal, Bendiksby & S. Ekman Pamplemousses: Jardin Botanique, on bark, 2016, Diederich 18256, Rivière Noire: East of Black River, from Visitor s Centre to Pilgrims Trail, on bark, 2016, Diederich BACTROSPORA A. Massal. cf. myriadea (Fée) Egea & Torrente. Reported from Mauritius by Crittenden et al. (1995). BAIDERA Ertz & Diederich, gen. nov. MycoBank MB Diagnosis: A genus of Roccellaceae characterized by a thick, crustose, ecorticate, compact thallus, lirelliform ascomata with a carbonized lecideine excipulum, a carbonized hypothecium extending down to the substrate, a pruinose and not tomentose hymenial disc, ascospores without a distinct gelatinous sheath and the psoromic acid chemosyndrome. Generic type: Baidera mauritiana Ertz & Diederich. Description. Thallus crustose, thick, compact, ecorticate. Photobiont trentepohlioid. Ascomata lirelliform; ascomatal margin lecideine; hymenial disc pruinose, not tomentose; excipulum dark brown to carbonized; hypothecium dark brown to carbonized, extending down to the substrate; hymenium K/I+ pale blue; paraphysoids mostly simple, sometimes branched (mainly in epihymenium), with a slightly enlarged apical cell; asci narrowly clavate, with a K/I+ blue internal wall (in particular when young), and a K/I+ blue ring around a tiny ocular chamber (Abietina-type according to Egea & Torrente 1994). Ascospores hyaline, fusiform, straight, without a distinct gelatinous sheath. Conidiomata pycnidial; conidiogenous cells simple, straight; conidia hyaline, simple. Chemistry: psoromic acid chemosyndrome. Notes. The new genus forms a distinct lineage in the family Roccellaceae, being somewhat related to the genera Gyrographa and Sigridea, but relationships between these genera are not supported (Fig. 4). It differs from all genera of Roccellaceae by the combination of a thick crustose, not byssoid thallus, lirelliform ascomata with a carbonized excipulum not covered by a thalline layer, a carbonized hypothecium extending down to the substrate, a pruinose and not tomentose hymenial disc, ascospores without a distinct gelatinous sheath, and a chemistry with psoromic acid as major substance. The genus is reminiscent of Lecanographa, but species of the latter have ascospores with a distinct gelatinous sheath, an ascus of the Grumulosa-type, and they belong to a distinct lineage in the family Lecanographaceae. Etymology. The new genus is dedicated to Cláudia Baider, curator of the Mauritius Herbarium (MAU), as an acknowledgement of her valuable help to us in exploring the lichens of Mauritius. Cláudia is very interested in the conservation of biodiversity in tropical terrestrial systems, in the impact of alien species in tropical forests, and in the restoration ecology and taxonomy of Mascarene flowering plants. Baidera mauritiana Ertz & Diederich, sp. nov. (Figs 3 4) MycoBank MB Diagnosis: The only species of Baidera is characterized by a pale greyish, almost white thallus, ascomata of mm, a K+ olivaceous green excipulum and 3( 4)-septate ascospores of µm. Type: Mauritius, Pamplemousses district, Pamplemousses, Sir Seewoosagur Ramgoolam Botanical Garden, S, E, alt. 80 m, on bark of Mangifera, 29 Dec. 2016, Ertz (MAU holotype, BR, herb. Diederich isotypes). Description. Thallus µm thick, continuous, pale greyish, almost white, ± smooth to rough, sometimes with areas appearing bullate, rimose to areolate, esorediate or rarely with whitish soredia, non-isidiate; medulla containing crystals (1 8 µm diam.) of calcium oxalate (tested with 25% H 2 SO 4 ), I+ red; hyphae hyaline, µm diam., I+ orange; prothallus dark brown, mm wide. Photobiont cells elongated, ~ µm. Ascomata lirelliform, simple, rarely with one ramification, semi-sessile, without constricted base, straight to strongly flexuose ( 2.7) mm, scattered or densely distributed; ascomatal margin prominent, slightly raised above the level of the hymenial disc, black, ± smooth, ± glossy; hymenial disc black, ± smooth, plane, covered by a thin layer of white pruina; excipulum µm thick laterally, K+ olivaceous green; hypothecium µm thick, K+ olivaceous green; hymenium not inspersed, pale yellowish to almost hyaline, µm tall, I+ dark red; subhymenium ~10 15 µm thick, I+ pale blue in parts; epihymenium pale orange-brown, I+ pale orange to pale blue, K (becoming almost hyaline); paraphysoids mostly simple, sometimes branched (mainly in epihymenium), µm, with a slightly enlarged and pale orange-brown apical cell of 2 3 µm in diameter; asci 8-spored, µm. Ascospores 3( 4)-septate, (25 ) ( 35) (4.5 ) ( 6) µm, ratio L/B (4.6 ) ( 6.4) (n = 26). Conidiomata either prominent, mm diam, with a thick thallus border and pore-like to short slit-like, slightly exposed, pale to dark brown opening, or immersed; wall rather inconspicuous, ~10 µm thick, pale yellowish; conidiogenous cells ~ µm; conidia straight, rarely slightly curved, ( 2) µm. Chemistry: thallus K, C, KC, PD+ distinctly yellow, UV ; psoromic (major) and three ± fatty acids of Rf 7, 10 and 17 detected by TLC (solvent B ). Ecology and distribution. The species is known from two localities in Mauritius, where it grows on the bark of big trees in parkland conditions. Notes. The new species is unique in having a thick pale greyish thallus containing psoromic acid, the lirelliform ascomata with a carbonized K+ olivaceous green excipulum, an exposed whitish pruinose hymenial disc, and 3-septate

11 P. Diederich & D. Ertz: First checklist of lichens and lichenicolous fungi from Mauritius 23 Figure 3. Baidera mauritiana [holotype]. A C thallus and ascomata; D section of ascoma, in water; E asci, in KI; F conidia, in water; G ascospores, in water. Scale bars: A = 2.5 mm; B C = 1 mm; D = µm; E = 10 µm; F G = 5 µm. Photos: D. Ertz.

12 24 Plant and Fungal Systematics 65(1): 13 75, 2020 large ascospores lacking a gelatinous sheath. Lecanactis californica is similar to our new species by the presence of psoromic acid and 3-septate ascospores, but differs by more roundish, unbranched, wider ascomata that are constricted at the base, slightly shorter ascospores (20 28 µm), and filiform conidia µm (Egea & Torrente 1994). The new species is reminiscent of Lecanographa, a genus in which L. follmanii appears to be the most similar to our new species, but it differs by much narrower ascospores (3 3.5 µm wide) with a distinct gelatinous sheath. Specimens Diederich 18734, and Ertz have only pycnidia, while specimen Diederich is sorediate. Etymology. The specific epithet refers to the occurrence in Mauritius. Additional specimens examined. MAURITIUS. Pamplemousses: Pamplemousses, Sir Seewoosagur Ramgoolam Botanical Garden, 80 m, S, E, on bark of a big tree, 2016, Ertz (pycnidia only); ibid., S, Lecanographaceae 36 Dendrographa leucophaea HQ Gyronactis asiatica KJ Crocellina cinerea KJ Vigneronia spierii KJ Vigneronia cypressi KJ Syncesia myrticola KJ Syncesia mascarena KJ Syncesia socotrana HQ Roccellina nigricans DQ Roccellina suffruticosa DQ Pseudoschismatomma rufescens KJ Ocellomma picconianum KJ Dirina astridae DQ Dirina ceratoniae GU Dirina candida KC Diromma dirinellum KJ Roccella allorgei DQ Roccella fuciformis DQ Roccella tinctoria DQ Schismatomma pericleum KJ Lecanactis epileuca KJ Lecanactis borbonica KJ Lecanactis abietina DQ Chiodecton leptosporum KJ Chiodecton natalense EU Sagenidiopsis isidiata KJ Isalonactis madagascariensis KF Austroroccella gayana KF Psoronactis dilleniana KJ Sigridea californica HQ Gyrographa saxigena KJ Roccellaceae Gyrographa gyrocarpa KJ Baidera mauritiana DE21443-hymenium Baidera mauritiana DE21443-thallus gen. & sp. nov Enterographa pitardii KJ Enterographa crassa EU Enterographa hutchinsiae EU Enterographa cf. tropica KJ Dichosporidium nigrocinctum KJ Dichosporidium brunnthaleri KJ Erythrodecton granulatum EU Mazosia dispersa KJ Mazosia carnea KJ Mazosia paupercula KJ Roccellographa cretacea HQ Dimidiographa longissima EU Pentagenella langei DQ Pentagenella gracillima HQ Roccellographaceae 60 Pentagenella fragillima DQ Combea mollusca DQ Dolichocarpus chilensis HQ Opegrapha niveoatra EU Opegrapha vulgata EU Nyungwea pallida KJ Nyungwea pyneei DE21450 sp. nov. Fouragea filicina EU Fouragea viridistellata EU Schizopelte parishii HQ Schizopelte californica HQ Schizopelte crustosa HQ Paralecanographa grumulosa HQ Paraschismatomma ochroleucum HQ Paraingaderia placodioidea HQ Ingaderia pulcherrima HQ Sparria cerebriformis HQ Opegraphaceae Sparria endlicheri HQ Dictyographa varians HQ Lecanographa hypothallina HQ Lecanographa dimelaenoides HQ Lecanographa dialeuca HQ Lecanographa uniseptata HQ Arthothelium galapagoense HQ Figure 4. Phylogeny of Arthoniales based on a data set of RPB2 sequences that resulted from a RAxML analysis. Maximum likelihood bootstrap values are shown above or near internal branches. Internal branches, considered strongly supported by both the RAxML and Bayesian analyses, are represented by thicker lines. The newly sequenced samples from Mauritius are highlighted and their names followed by collecting numbers of authors, which act as specimen and sequence identifiers.

13 P. Diederich & D. Ertz: First checklist of lichens and lichenicolous fungi from Mauritius E, on bark of trees, 2016, Diederich (fertile and sorediate). Moka: Réduit, State House Park, on bark, 2019, Diederich 18734, 18741, & Ertz BIATORA Ach. leucoxantha (Spreng.) Bél. Brigantiaea leucoxantha BIATOROPSIS Räsänen Biatoropsis millanesiana Diederich & Wedin, sp. nov. (Figs 5 6) MycoBank MB Diagnosis: Characterized by large, brown, relatively dark basidiomata, and 3-septate basidia with the three lower cells laterally often elongating at maturity. Type: Mauritius, Rivière Noire, Chamarel, Ebony Forest, around viewpoint, S, E, alt. 350 m, on branches of trees, on Usnea exasperata s. l., 8 Aug. 2016, Diederich (MAU holotype, BR, MAF, S, herb. Diederich isotypes). Description. Basidiomata inducing the formation of convex, basally constricted galls, sometimes slightly tuberculate when mature, waxy gelatinous when wet, pale brown to more frequently dark brown or blackish, (0.3 ) ( 2.5) mm diam. Context hyphae thin-walled, 2 3 μm diam., clamp connections not observed. Haustorial branches frequent, mother cell spherical to subspherical, μm, haustorial filament μm diam. Hymenium hyaline, containing numerous probasidia; probasidial initials clavate to subcylindrical; basal clamp not observed. Basidia, when mature, 4-celled, with three transverse septa, not or slightly constricted at the septa, the lower cell with an attenuated stalk-like base, often longer than the upper cells, μm (incl. stalk-like base, excl. epibasidia), lower part of the stalk-like base 2 4 μm diam.; the three lower cells laterally much elongate at maturity, sometimes giving the appearance of immature independent basidia, 4 6 µm thick. Epibasidia up to 50 µm long. Basidiospores globose to ellipsoid, (4 )5 8 (5.5 )6 9( 11) μm, ratio L/B 0.6 1, with a distinct apiculus, ~1 μm diam. Asexual morph not observed. Hosts and distribution. Lichenicolous on the thallus of U. exasperata s. l., on which it is very abundant in Mauritius, Rodrigues and the Seychelles (Praslin) in the Indian Ocean. Usnea exasperata currently seems to represent a heterogeneous assemblage of several species, but no taxonomic and phylogenetic revision is available yet to identify them. Notes. Millanes et al. (2014; 2016) recognized an independent evolving lineage provisionally named Biatoropsis sp. F. Specimens from this clade were reported from Usnea ceratina, U. exasperata, U. hirta and U. rubicunda. Millanes et al. (2016) have not been able to identify any morphological or ecological characters that could distinguish specimens in this clade from Biatoropsis usnearum s.str. and preferred to wait for a formal description until more material is available. Our rich material from several localities in Mauritius, incl. Rodrigues, allowed us to better understand the phylogenetic relationships between the specimens included in B. sp. F (Fig. 6). Our results show that the clade formerly recognized as Biatoropsis sp. F represents in reality at least two distinct species, one confined to Usnea exasperata s.lat. in the Indian Ocean, and another one on U. rubicunda (with a further specimen known from U. ceratina [host identified by C. Truong; TLC: diffractaic]). Populations on U. hirta reported from Arizona by Millanes et al. (2016) are not considered here, owing to the deviating morphology of basidiomatal galls (broad, almost disk-like, concolorous to the host thallus), and will be treated elsewhere. The available nice and richly fertile material from Mauritius and Rodrigues pemits us to describe the species formally here. The main characterizing feature may be the 3-septate basidia, in which the three lower cells elongate laterally at maturity, giving the appearance of several individual aseptate basidia (Fig. 5I). Such basidia had not been observed in the Seychelles specimen by Millanes et al. (2016), and rich fertile material seems to be needed to observe them. Similar basidia are also known from Biatoropsis hafellneri, a species confined to the Usnea fragilescens aggregate, but in that species they are always 1-septate, and basidiomata are pale orange or brown. Basidiomata of Biatoropsis minuta are always smaller, mm diam., and this species is known only from the two related Usnea barbata and U. lapponica. Biatoropsis protousneae has large, often flattened basidiomata and is confined to Protousnea dusenii. Biatoropsis usnearum s.str. has large basidiomata ranging from pale brown to blackish, but typically pinkish to orange-brown; European specimens appear to grow exclusively on the Usnea florida/subfloridana complex, while populations from other continents are more diverse regarding host selection (Millanes et al. 2016). Crombie (1876b) described the new Usnea dasypogoides from Rodrigues and mentioned that scattered «cephalodia» not unfrequently occur, suggesting basidiomata of the new Biatoropsis. However, no such basidiomata are seen in online photographs of syntypes of U. dasypogoides in E, G and H. Etymology. The new species is dedicated to our friend Ana Millanes, mycologist at King Juan Carlos University, Madrid, to honour her huge contribution to the study and knowledge of heterobasidiomycetes in general and especially of lichenicolous Tremellales. Additional specimens examined. MAURITIUS (all on Usnea exasperata s. l.). Plaines Wilhems: Curepipe, Curepipe Botanic Gardens, 2016, Diederich (specimen kept under U. exasperata s. l.). Rivière Noire: Same locality as type, 2019, Diederich & Ertz 23556A. Rodrigues: N of Grande Montagne, near road bifurcation W of Brûlé, 2019, Diederich & Ertz (sub Usnea); Grande Montagne Nature Reserve, 2019, Diederich & Ertz 23722, 23723; SE of Mont Lubin, Mont Limon, near the top, 2019, Diederich SEYCHELLES. Praslin: Praslin National Park, SE of Vallée de Mai, along trail to Glacis Noir and fire tower, S, E, 2015, Diederich 18087B (SEY, herb. Diederich). BILIMBIA De Not. lobulata (Sommerf.) Hafellner & Coppins [ Lecanora murorum var. lobulata (Sommerf.) Schaer.]. Reported from Rodrigues, on rocks, 1874, Balfour 2350, by Crombie (1876b). BOGORIELLA Zahlbr. leuckertii (D. Hawksw. & J. C. David) Aptroot & Lücking Lichenologist 48: 911 (2016); Mycomicrothelia leuckertii D. Hawksw. & J. C. David, in David & Hawksworth, Biblioth. Lichenol. 57: 98 (1995). Type: Plaines Wilhems, Vacoas, ingressus sylvae Macchabeae, on bark of Syzygia jambosa, 11 June 1990, Hawksworth (K-IMI ,

14 26 Plant and Fungal Systematics 65(1): 13 75, 2020 holotype) (David & Hawksworth 1995; Crittenden et al. 1995; Aptroot & Lücking 2016: 911) thelena (Ach.) Aptroot & Lücking [ Verrucaria thelena Ach.]. Sur l écorce des Rubiacées et particulièrement sur celle des Ixora, sur celle des Strychnos et de plusieurs Térébinthacées (Bélanger 1834). BRIGANTIAEA Trevis., nom. rej. leucoxantha (Spreng.) R. Sant. & Hafellner Biatora leucoxantha (Spreng.) Bél.; Lopadium leucoxanthum (Spreng.) Zahlbr. Rivière Noire: Trail from Plaine Champagne towards Piton Figure 5. Biatoropsis millanesiana [holotype]. A type locality in Mauritius; B C basidiomata; D E hymenium, showing basidia, epibasidia and one basidiospore attached to an epibasidium; F haustorial branches; G young, 3-septate basidium; H basidium with laterally slightly elongate cells; I J mature basidia with four laterally elongate and diverging cells (in I shown by arrows); K basidiospores. D K in a mixture of 5% KOH, phloxine B and Congo Red. Scales: B C = 200 µm; D J = 10 µm; K = 5 µm. Photos: P. Diederich.

15 P. Diederich & D. Ertz: First checklist of lichens and lichenicolous fungi from Mauritius Biatoropsis sp. A1 - AM296 Biatoropsis sp. A1 - AM Biatoropsis sp. A1 - AM112 Biatoropsis sp. A1 - AM143 Biatoropsis protousneae - AM214 Biatoropsis protousneae - AM141 Biatoropsis protousneae - AM215 Biatoropsis protousneae - AM142 (T) Biatoropsis minuta - AM137 (T) Biatoropsis minuta - AM172 Biatoropsis minuta - CO294 Biatoropsis minuta - AM229 Biatoropsis usnearum - AM171 Biatoropsis usnearum - AM196 Biatoropsis usnearum - AM Biatoropsis usnearum - AM202 Biatoropsis hafellneri - AM299 Biatoropsis hafellneri - AA10 (T) 65 Biatoropsis sp. E - AM213 Biatoropsis millanesiana - AM567 (Usnea exasperata s.l. Seychelles) Biatoropsis millanesiana - AM1171 (Usnea exasperata s.l. Mauritius) Biatoropsis millanesiana - AM784 (Usnea exasperata s.l. Mauritius) (T) Biatoropsis millanesiana - AM1026 (Usnea exasperata s.l. Mauritius) Biatoropsis millanesiana - AM1168 (Usnea exasperata s.l. Rodrigues) Biatoropsis millanesiana - AM1170 (Usnea exasperata s.l. Rodrigues) 99 Biatoropsis millanesiana - AM1169 (Usnea exasperata s.l. Rodrigues) Biatoropsis sp. F - AM576 (Usnea rubicunda France) Biatoropsis sp. F - AM166 (Usnea ceratina U.S.A.) Biatoropsis sp. F - AM10 (Usnea rubicunda New Zealand) 98 Biatoropsis sp. F - AM1040 (Usnea rubicunda New Zealand) Biatoropsis sp. F - AM295 (Usnea rubicunda New Zealand) Tremella cetrariicola - AM Figure 6. Phylogram showing the position of the new species Biatoropsis millanesiana (blue box), based on ITS and nulsu sequences, corresponding to the best tree recovered in the maximum likelihood analysis, with information on ML bootstrap values added. Thick branches indicate nodes with ML bootstrap values over 75%. Type specimens are indicated by (T). de la Petite Rivière Noire, on bark, 2016, Diederich 18421, 18422; Chamarel, Ebony Forest, along trail W of viewpoint, on bark, 2019, Ertz Port Louis and Moka: Along trail from Moka to Le Pouce, on bark, 2019, Ertz Previously reported from Mauritius Sur les bois morts by Bélanger (1834), by Lindau (1908), from BM, G and H by Hafellner (1997: 55), and from Rodrigues (BM) by Hafellner (1997: 55). tricolor (Mont.) Trevis. Hafellner (1997: 71) wrote under Lecidea leucoxantha var. ochrocarpa that Until now only B. tricolor has been found in Mauritius. This is certainly a lapsus, as this author reported having studied several specimens of B. leucoxantha from Mauritius and Rodrigues, while B. tricolor is known from Madagascar and Reunion but not from Mauritius. BROWNLIELLA S. Y. Kondr., Kärnefelt, Elix, A. Thell & Hur cinnabarina (Ach.) S. Y. Kondr., Kärnefelt, A. Thell, Elix, J. Kim, A. S. Kondr. & Hur [ Caloplaca cinnabarina (Ach.) Zahlbr., Lecanora cinnabarina Ach.]. Reported from Rodrigues, on rocks, 1874, Balfour 2301, by Crombie (1876b). BUELLIA De Not. continens (Nyl. ex Cromb.) Zahlbr., Cat. Lich. Univ. 7: 346 (1931); Lecidea continens Nyl. ex Cromb., J. Bot. 14: 264 (1876). Type: Rodrigues, on rocks, 1874, Balfour 2343 (BM, H) (Crombie 1876a, b). geophila (Flörke ex Sommerf.) Lynge [= Lecidea triphragmia Nyl.]. Reported from Rodrigues, on bark of trees, 1874, Balfour 2368, by Crombie (1876b). immutans (Nyl. ex Cromb.) Zahlbr., Cat. Lich. Univ. 7: 368 (1931); Lecidea immutans Nyl. ex Cromb., J. Bot. 14: 264 (1876). Type: Rodrigues, on rocks, 1874, Balfour 2221 (BM, H) (Crombie 1876a, b). spuria (Schaer.) Anzi [ Lecidea spuria Schaer.]. Reported from Rodrigues, on rocks, 1874, Balfour 2351, by Crombie (1876b). BULBOTHRIX Hale aff. johannis D. M. Masson, Benatti & Sérus. Plaines Wilhems: Le Pétrin, along trail W of Pétrin Information Centre, up to 600 m W of first viewpoint, on bark,

16 28 Plant and Fungal Systematics 65(1): 13 75, , Diederich Savanne: Along trail to Mt Cocotte, on bark, 2019, Diederich Reported by Masson et al. (2015) from Plaines Wilhems, near Midlands, Vaughan L/6 (BM) (Hale 1976: 24, as B. suffixa), along the path from Plaine Champagne towards Piton de la Petite Rivière Noire, 1991, Krog & Timdal (O), Le Pouce, 1991, Krog & Timdal (O), Pétrin heath, 1991, Krog & Timdal (O), and Mt Cocotte, 1991, Krog & Timdal (O). Following Masson et al. (2015), the material from Mauritius probably is a taxon different from B. johannis but phylogenetically closely related to it. suffixa (Stirt.) Hale. The Mauritius specimen previously published under this name by Hale (1976) was referred to Bulbothrix aff. johannis by Masson et al. (2015). The report from Mt Cocotte, 1991, Krog & Timdal (O) (Lücking & Timdal 2016: 194) almost surely also refers to B. aff. johannis. BUNODOPHORON A. Massal. australe (Laurer) A. Massal. [ Sphaerophorus australis Laurer]. Reported from Mauritius auf Erde by Lindau (1908). melanocarpum (Sw.) Wedin [= Sphaerophorus compressus Ach.]. Reported from Mauritius by Daruty (1873, sub Sphaerophoron compressum ). BYSSOCAULON Mont. molliusculum Nyl. Crocynia molliuscula CALOPLACA Th. Fr. aurantiella (Nyl. ex Cromb.) C. Moreau & M. Moreau, Rev. Bryol. Lichén. 20: 193 (1951); Lecanora aurantiella Nyl. ex Cromb., J. Bot. 14: 263 (1876). Type: Rodrigues, on rocks, 1874, Balfour 2317 (BM, H) (Crombie 1876a, b). bassiae (Ach.) Zahlbr. Gyalolechia bassiae cinnabarina (Ach.) Zahlbr. Brownliella cinnabarina diplacia var. carneofusca (Nyl. ex Cromb.) Zahlbr., Cat. Lich. Univ. 7: 114; Lecanora carneofusca Nyl. ex Cromb., J. Bot. 14: 263 (1876). Type: Rodrigues, on rocks, 1874, Balfour 2293 (BM, H, M, UPS-L049836) (Crombie 1876a, b). glaucofuscula (Nyl. ex Cromb.) Zahlbr., Cat. Lich. Univ. 7: 141 (1930); Lecanora glaucofuscula Nyl. ex Cromb., J. Bot. 14: 263 (1876). Type: Rodrigues, on rocks, 1874, Balfour 2216 (BM, H) (Crombie 1876a, b). Lecanora glaucofuscula f. biatoroidea Cromb., Journ. Linn. Soc., Bot. 15: 437 (1876). Type: Rodrigues, on rocks, 1874, Balfour (BM). Probably belongs to Caloplaca s.lat. but has never been combined there. saxicola (Hoffm.) Nordin [= Placodium murorum DC.]. Reported from Mauritius (herb. Fée) by Nylander (1859: 257). CELOTHELIUM A. Massal. Tomasellia zollingeri Müll. Arg. Hedwigia 31: 287 (1892). Type: Summit of Pouce (BM; G , syntypus). Müller (1892) suggested that this species belongs to Celothelium, a view shared by Aguirre-Hudson (1991). David & Hawksworth (1995: 105) examined the BM specimen found to belong to Celothelium, however the nature of its relationship with C. aciculifera (Nyl.) Vain. has to be clarified and will be included in a further paper. CETRARIA Ach. aculeata (Schreb.) Fr. The report from Mauritius by Daruty (1873) almost surely refers to specimen Bojer (MAU L1885!, sub C. aculeata), which belongs to Cladia gorgonea. CETRELIA W. L. Culb. & C. F. Culb. olivetorum (Nyl.) W. L. Culb. & C. F. Culb. [ Parmelia olivetorum Nyl.]. Reported from Mauritius by Daruty (1873). CHAPSA A. Massal. alborosella (Nyl.) A. Frisch Plaines Wilhems: Le Pétrin, between Pétrin Information Centre and first viewpoint along trail to the west, on a branch, 2016, Diederich A pantropical species, new for Mauritius. Chapsa alletii Diederich & Ertz, sp. nov. (Fig. 7) MycoBank MB Diagnosis: Characterized by apothecia mm diam., a white pruinose disc, a margin with a bright red, K+ green inner surface, and hyaline, 4 7-septate ascospores, µm. Type: Mauritius, Plaines Wilhems, Black River Gorges National Park, Le Pétrin, between Pétrin Information Centre and first viewpoint along trail to the west, S (± 0 m), E (± 300 m), alt m, on a branch of a tree, 1 Aug. 2016, Diederich (MAU holotype). Description. Thallus light brown, smooth to uneven; cortex µm thick, dense, formed of periclinal hyphae; photobiont layer and medulla with irregularly dispersed clusters of calcium oxalate crystals. Apothecia immersed, angular-rounded, mm diam.; disc exposed, flesh-coloured, covered by a white to pink pruina especially dense in the centre and thus appearing as whitish, occasionally reddish in the centre; margin fused with the exciple, lobulate, lobes recurved, with a bright red inner surface, red pigment K+ green. Columella absent. Excipulum prosoplectenchymatic, reddish brown, K+ green; periphysoids present, distinct, µm long. Hymenium μm high, clear; epihymenium hyaline or brownish, granulose; paraphyses unbranched, µm thick, apically not or slightly swollen, not spinulose, surrounded by minuscule granules. Asci 8-spored, μm. Ascospores when young thin-walled, when mature fusiform to narrowly ellipsoid, colourless, 4 7-septate, with relatively thick septa and ellipsoidal lumina, μm, I, often surrounded by a relatively thin halo. Pycnidia not observed. Chemistry: because of the rather small size of the single specimen, no TLC has been done; however, the red, K+ green pigment of the apothecial margin most probably represents isohypocrel line, known from similarly coloured Cruentotrema species (Rivas Plata et al. 2012). Ecology and distribution. The only known specimen grows on the bark of a 7 mm thick branch of a tree in an disturbed and open forest. It was collected along a trail on the west of Le Pétrin and should be searched for in similar habitats in Mauritius. Notes. The new species is remarkable and distinct from all known Chapsa species by its bright red, K+ green apothecial

17 P. Diederich & D. Ertz: First checklist of lichens and lichenicolous fungi from Mauritius 29 Figure 7. Chapsa alletii [holotype]. A brownish thallus and red apothecia; B section through apothecial margin, showing hymenium, reddish brown raised apothecial margin, and layer of periphysoids, in water; C hymenium with mature 8-spored asci, in water; D paraphyses apically surrounded by granules, in water; E F hymenium, in Lugol; G ascospore, showing halo, in water; H ascospores, in Lugol. Scales: A = 500 µm; B = 20 µm; C, E F = 10 µm; D, G H = 5 µm. Photos: P. Diederich.

18 30 Plant and Fungal Systematics 65(1): 13 75, 2020 margin. Apart from this character, it fits the genus rather well (Frisch 2006). It needs to be compared with genera that resemble or have recently been segregated from Chapsa. Acanthotrema A. Frisch differs by apically spinulose paraphyses and periphyses, and thin-walled ascospores (Sipman et al. 2012). Chroodiscus (Müll. Arg.) Müll. Arg. differs by thin-walled ascospores, missing periphyses, and a foliicolous habitat (Frisch 2006). The monotypic Reimnitzia Kalb differs, among others, by the brown, muriform ascospores and the thick-walled young ascospores (Frisch 2006). Gintarasia Kraichak, Lücking & Lumbsch includes species with large apothecia up to 4 mm diam.; it differs from Chapsa by a more complex chemistry, and from our new species by the muriform ascospores; phylogenetically it is not related to Chapsa (Kraichak et al. 2013). Pseudochapsa Parnmen, Lücking & Lumbsch differs by amyloid ascospores and a rarely recurved apothecial margin (Parnmen et al. 2012). Nitidochapsa Parnmen, Lücking & Lumbsch differs by dark brown, amyloid ascospores (Parnmen et al. 2013). In addition to Chroodiscus (see above), a few thelotrematoid genera have species with a coloured apothecial margin. Cruentotrema Rivas Plata, Papong, Lumbsch & Lücking is distinguished by a half-carbonized upper exciple, the missing periphysoids, and apothecia with a disc hidden by a partially splitting thallus layer, which exposes a white or dark red medulla (simulating a red apothecial disc); the red pigment reacting K+ green, almost surely identical to the pigment in our new species, has been identified by Rivas Plata et al. (2012) as isohypocrelline. Gyrotrema Frisch differs by gyrotremoid apothecia, regenerating with new hymenia and excipula formed centrifugally in concentric circles; the bright orange to cinnabar-red or pink disc reacts K+ purple and therefore does not represent isohypocrelline (Frisch & Kalb 2006). A few known species with chroodiscoid apothecia have a coloured disc, such as Astrochapsa magnifica (Berk. & Broome) Parnmen, Lücking & Lumbsch (disc orange), A. waasii (Hale) Parnmen, Lücking & Lumbsch (disc pink-purple, K+ dark purple) or Chapsa rubropruinosa Messuti & Codesal (disc red-brown, K+ bluish), but none of them has a brightly coloured apothecial margin (Rivas Plata et al. 2010). The genus Astrochapsa Parnmen, Lücking & Lumbsch is phylogenetically distinct, differing from Chapsa s.str. in the more frequently densely corticate thallus, the mostly recurved apothecial margin, and the almost exclusively subdistoseptate, non-amyloid ascospores (Parnmen et al. 2012). All these characters are shared by our new species but also by some species now included in Chapsa. Without molecular data, we are thus unable to decide if the new species is related to Chapsa s.str. or to Astrochapsa, or if it pertains to another genus owing to the distinct red pigmentation. Etymology. The new species is dedicated to Mr Mario Allet, officer of the National Parks and Conservation Services in Mauritius and an excellent botanist, to thank him for his kindness during our 2016 and 2019 collecting trips, and for having guided us to some interesting sites, including the type locality of the new species. CHIODECTON Ach. confusum Wedd. ex Nyl., Bull. Soc. Linn. Normandie, sér. 2, 7: 173 (1874 [ 1873 ]); C. confusum Wedd., in Daruty, Trans. Roy. Soc. Arts Mauritius, n.s. 7: 163 (1873), nom. nud. Original material: Corticola in insula Mauritii. CHRYSOTHRIX Mont. candelaris (L.) J. R. Laundon [= Lepraria flava (Willd.) Ach.]. The specimens reported from Mauritius under these names (Crittenden et al. 1995; Daruty 1873; Laundon 1981) probably belong to the tropical Chrysothrix xanthina. xanthina (Vain.) Kalb = Crocynia mauritiana Hue, Bull. Soc. Bot. France 71: 337 (1924). Type: sur un Manguier, au quartier des Pamplemousses, chez Mr Bouton, Daruty 25 (PC, holotype) (Hue 1924, Laundon 1981: 110, 2008: 412, as Chrysothrix candelaris). Moka: Réduit, State House Park, on bark of Pinus, 2019, Diederich 18716; Réduit, close to Mauritius Herbarium, on bark of Pinus, 2019, Diederich & Ertz 23240A; ibid., on bark, Ertz Pamplemousses: Jardin Botanique, on bark, 2016, Diederich 18254, (MAU). Rivière Noire: Chamarel, Ebony Forest, close to park buildings, on bark, 2016, Diederich (fertile). The specimens reported from Souillac, on trunk of Casuarina equisetifolia, 14 m, 1890, Johnston 2 (BM) by Laundon (1981: 110, as C. candelaris), and from Pamplemousses Botanical Garden, on bark of Arecaceae, 1990, Hawksworth (K-IMI) by Crittenden et al. (1995, as C. candelaris), are provisionally included here in C. xanthina. CLADIA Nyl. gorgonea (Eschw.) Parnmen & Lumbsch Plaines Wilhems: Le Pétrin, heathland NW of Pétrin Information Centre, terricolous, 2016, Diederich Without locality: Bojer (MAU L1885!, sub Cetraria aculeata). Our recent specimen is extremely reduced but typical for this species. CLADONIA P. Browne balfourii Cromb. = Cladonia macilenta borbonica Nyl. Cladonia fimbriata var. borbonica (Nyl.) Vain. Reported from Mauritius, Robillard: in herb. Meo by Vainio (1894: 344). Ahti (pers. comm.) saw a correctly identified specimen: Ile de France, Sur les vieux bois pourris, abattus dans les forêts de Pouce, c. 1840, Lepervanche-Mézières 65 (PC-Thuret). cartilaginea Müll. Arg. Ahti (pers. comm.) saw a specimen from Pétrin heath, 600 m, unter Gebüsch am Erdboden auf Holz, 1980, Schultze-Motel (B ). ceratophyllina (Nyl.) Vain. [ Cladonia degenerans var. ceratophyllina Nyl.]. Reported from Mauritius by Daruty (1873). confusa R. Sant. Plaines Wilhems: Le Pétrin, heathland NW of Pétrin Information Centre, terricolous, 2016, Diederich Previously reported from Mauritius by Ahti & Aptroot (1992), from Pétrin, 1967, Henderson (H) by Ruoss & Ahti (1989), and from Pétrin, 1990, Hawksworth (K-IMI, det. Ahti) by David & Hawksworth (1995) and Crittenden et al. (1995). Ahti (pers. comm.) saw additional specimens, both

19 P. Diederich & D. Ertz: First checklist of lichens and lichenicolous fungi from Mauritius 31 representing morph leptoclada: Native Plants Protected Forest, 1961, Fukishima (H, TNS); Pétrin, 1967, Henderson (E, H, HMAS). Further unpublished specimens from Pétrin or without accurate locality, some identified as C. alpestroides Abbayes or C. leptoclada Abbayes, are kept in CANB, O, S, UPS and WIS. degenerans var. ceratophyllina Nyl. Cladonia ceratophyllina didyma (Fée) Vain. Ahti (pers. comm.) saw a specimen from Pétrin heath, 1961, Sauer 19 (S L32152). fimbriata (L.) Fr. Reported from Mauritius, Robillard, and from Rodrigues, 1874, Balfour (BM) by Vainio (1894: 253). fimbriata var. borbonica (Delise) Vain. Cladonia borbonica fimbriata var. radiata (Schreb.) Cromb. Reported from Mauritius by Daruty (1873). floerkeana (Fr.) Flörke. Reported from Mauritius by Lindau (1908). gigantea (Bory) H. Olivier Plaines Wilhems: Le Pétrin, heathland NW of Pétrin Information Centre, terricolous, 2016, Diederich & Ertz (TLC of 23329: thamnolic, solvents A, B ). Previously reported from Mauritius (Les Mares and Pétrin) by Ahti (1977), and from Pétrin, 1990, Hawksworth (K-IMI, det. Ahti) by David & Hawksworth (1995) and Crittenden et al. (1995). Further unpublished specimens from Pétrin or without locality are kept in CANB, MAU, O, PTBG and WIS. intermediella Vain. Acta Soc. Fauna Fl. Fenn. 10: 12 (1894). Type: Ad terram in summo monte Pouce in Mauritio, Ayres (BM holotype, fide Ahti, pers. comm.). The species is known also from Reunion and continental Africa (Swinscow & Krog 1988). macilenta Hoffm. = Cladonia balfourii Cromb., J. Bot. 14: 262 (1876). Type: Rodrigues, on dead (rotten) stumps of trees, 1874, Balfour 2204 (BM, lectotype, designated by Ahti 2000; E, FH- Dodge, H-NYL 39124, UPS, isolectotypes). Previously reported from Mauritius by Daruty (1873) and Lindau (1908). Further unpublished specimens from Curepipe Botanical Garden, Mt Cocotte and Pétrin, collected by Krog & Timdal in 1991, are kept in O. macilenta var. polydactyla (Flörke) Cladonia polydactyla mauritiana Ahti & J. C. David in David & Hawksworth, Biblioth. Lichenol. 57: 94 (1995). Type: Mauritius, Black River, east of Chamarel, alt. 300 m, on soil by road, 16 June 1990, Hawksworth (K-IMI holotype, H isotype). Plaines Wilhems: Le Pétrin, heathland NW of Pétrin Information Centre, terricolous, 2016, Diederich 18371; ibid., 2019, Ertz 23330, 23337, (TLC: fumarprotocetraric, solvents A, B ); Curepipe, Curepipe Botanic Gardens, over mosses, at the base of a tree, 2016, Diederich A further unpublished specimen from Pétrin, Schultze-Motel (B) was studied by Ahti (pers. comm.). The species has also been reported from Reunion, Comoro Is., Seychelles, India, Malaysia and Thailand (Ahti et al. 2002). medusina (Bory) Nyl. = Cladonia medusina var. dealbata Vain.; = Cladonia medusina var. luteola (Bory) Vain. Plaines Wilhems: Le Pétrin, heathland NW of Pétrin Information Centre, terricolous, 2016, Diederich Savanne: Road from Le Pétrin to Chamouny, beginning of trail to Montagne Cocotte, on dead wood, 2016, Diederich Previously reported from Mauritius by Hue (1898) and Vainio (1887: , as var. dealbata and var. luteola), and from Pétrin, 1990, Hawksworth (K-IMI, det. Ahti) by David & Hawksworth (1995) and Crittenden et al. (1995). Further unpublished specimens from Pétrin are kept in MAU, O, PTBG, US and WIS. pityrea var. subareolata Vain. Reported from Mauritius by Vainio (1894). polydactyla (Flörke) Spreng. Reported from Mauritius by Daruty (1873, as C. macilenta var. polydactyla Flk. ). pycnoclada (Pers.) Nyl. The report from Mauritius, Bojer, by Vainio (1887: 38) obviously refers to C. confusa. rangiferina (L.) Weber ex F. H. Wigg. The report from Mauritius, 1825, Despreaux (PC) by Vainio (1887: 13) obviously refers to C. gigantea. squamosa (Scop.) Hoffm. Reported from Mauritius, Gardner? by Vainio (1887: 417) uncialis (L.) Weber ex F. H. Wigg. The report from Mauritius by Daruty (1873) may refer to specimen Bojer 14 (MAU L189!, sub Cladonia uncialis), which is an unidentified Cladia. varians Vain. ex Ahti ( )= Cladonia varians var. glaucoflava Vain., in Hue, Lichenes extra-europaei: 267 (1898), nom. inval. Original material: three specimens were mentioned in the original publication from Reunion, Mauritius (1890) and Madagascar, all leg. fr. Rodriguez. ( )= Cladonia varians var. erythrospermoides Vain., in Hue, Lichenes extra-europaei: 267 (1898), nom. inval. Original material: two specimens were mentioned in the original publication from Reunion and Mauritius (1890 and 1891), both leg. fr. Rodriguez. Following Ahti et al. (1987: 94), Vainio (in Hue 1898) reported C. varians from Reunion, Mauritius and Madagascar, and the author Ahti has confirmed his identifications (in PC and TUR-V). The PC online database, consulted on 17 Febr. 2019, contains a specimen from Reunion and one from Madagascar, but no specimen from Mauritius. The report by Swinscow & Krog (1988) from Rodrigues appears to be based on confusion with the name of the collector of the type material, fr. Rodriguez (Ahti & Aptroot 1992). COCCOCARPIA Pers. adnata L. Arvidss. Opera Bot. 67: 42 (1982). Type: Plaine Champagne, 20 km S of Rose Hill, 700 m, on trunks of a small tree in submontane scrub, 14 April 1979, Arvidsson & Nilsson 2660 (GB holotype). A species widely distributed in the Paleotropics (Arvidsson 1982).

20 32 Plant and Fungal Systematics 65(1): 13 75, 2020 erythroxyli (Sprengel) Swinscow & Krog = Peltidea floerkeana Laurer, Linnaea 2: 43 (1827). Type: In insula St. Mauritii (type of Peltidea floerkeana not traced, probably destroyed; Laurer 1827, tab. I, fig. 3, lectotype, designated by Arvidsson 1982: 57). = Coccocarpia molybdaea Pers. Reported from Mauritius by Daruty (1873), from 4 specimens (GB, PC) by Arvidsson (1982: 62), from Ile aux Aigrettes (BM, det. James) by Parnell et al. (1989), and from Rodrigues, on branches of trees, 1874, Balfour 2243 by Crombie (1876b). Further unpublished specimens from Morne du Grand Port and Ile aux Aigrettes are kept in MAU and O. molybdea Pers. = Coccocarpia erythroxyli palmicola (Sprengel) Arv. & D. J. Galloway Plaines Wilhems: Curepipe Botanic Gardens, on bark, 2019, Diederich 19111, & Ertz Rivière Noire: Chamarel, Ebony Forest, around viewpoint, on bark, 2016, Diederich 18528, 18529; ibid., on termite nest, 2019, Ertz 23563; ibid., along trail W of viewpoint, on bark, 2019, Diederich Previously reported from Mauritius (GB, 12 specimens) by Arvidsson (1982: 76), from Ile aux Aigrettes (BM, det. James) by Parnell et al. (1989), from Savanne, Plaines Champagne, at viewpoint of Black River Gorge, 1990, Hawksworth (K-IMI) by Crittenden et al. (1995), and from Grand Port, Bambou Mountains, 1991, Krog & Timdal (O) by Lücking & Timdal (2016). Further unpublished specimens from Curepipe (Trou aux Cerfs, Botanical Garden), Black River (La Mivoie), Grand Port (Ile aux Aigrettes), Pétrin, Macchabee Kiosk and Mt Cocotte, collected by Krog & Timdal in 1991, are kept in O. pellita (Ach.) Müll. Arg. Plaines Wilhems: Curepipe, Trou aux Cerfs, along road surrounding the crater, on bark, 2016, Diederich 18282; Le Pétrin, between Pétrin Information Centre and first viewpoint along trail to the west, on bark, 2016, Diederich 18318, Rivière Noire: E of Black River, from Visitor s Centre to Pilgrims Trail, on bark, 2016, Diederich 18483, 18484; Trail from Plaine Champagne towards Piton de la Petite Rivière Noire, on bark, 2016, Diederich 18614, 18615; Brise Fer Forest, on bark, 2019, Diederich Previously reported from Mauritius by Lindau (1908) and from one specimen in GB by Arvidsson (1982: 79). Further unpublished specimens from Pétrin, Macchabee Forest, Trou aux Cerfs and Mt Cocotte, collected by Krog & Timdal in 1991, are kept in O. pruinosa Arv. Reported from Grand Port, Mt des Créoles, 1991, Krog & Timdal (O) by Lücking & Timdal (2016: 198). Further unpublished specimens from Mt Cocotte, Piton de la Petite Rivière Noire and Macchabee Forest, collected by Krog & Timdal in 1991, are kept in O. smaragdina Pers. Plaines Wilhems: Curepipe Botanic Gardens, on bark, 2019, Diederich & Ertz Rivière Noire: Trail from Plaine Champagne towards Piton de la Petite Rivière Noire, on bark, 2016, Diederich 18612, Port Louis and Moka: Along trail from Moka to Le Pouce, on rock, 2019, Ertz Savanne: Along trail to Mt Cocotte, on bark, 2019, Diederich 18858, & Ertz Previously reported from Mauritius, 1876, Robillard (G) by Arvidsson (1982: 86), by Crittenden et al. (1995), and from Grand Port, Mt des Créoles, 1991, Krog & Timdal (O) by Lücking & Timdal (2016: 198). Further unpublished specimens from Mt Cocotte, Piton de la Petite Rivière Noire and Curepipe Botanical Garden, collected by Krog & Timdal in 1991, are kept in O. stellata Tuck. Reported from Plaine Champagne, 20 km S of Rose Hill, 1979, Arvidsson & Nilsson 2659 (GB) by Arvidsson (1982: 89). COENOGONIUM Ehrenb. leprieurii (Mont.) Nyl. Reported from Mauritius by Hue (1892: 181). COLLEMA Weber ex F. H. Wigg. azureum (Sw.) Ach. Leptogium azureum (Sw.) Mont. burgessii (L.) Ach. Leptogium burgessii byrsinum Ach. Physma byrsinum coilocarpum (Müll. Arg.) Zahlbr. Cat. Lich. Univ. 3: 34 (1924 [ 1925 ]); Synechoblastus coilocarpus Müll. Arg., Lichenol. Beitr. 34, Flora 74 (1891): 107. Type: Corticola in insula Mauritii, Dr Cupes, L[ouis] B[outon] n (G , lectotype; K, isolectotype) (Degelius 1974: 145). leptaleum var. biliosum (Mont.) Degel. Reported from Mauritius by Crittenden et al. (1995). leptaleum Tuck. var. leptaleum =? Synechoblastus robillardii Müll. Arg., Lichenol. Beitr. 6, Flora 60: 471 (1877); Collema robillardii (Müll. Arg.) Stizenb., Lichenaea afric. 1, Ber. Thätigk. St. Gallischen Naturwiss. Ges : 119 (1890), nom. conf. Type: Mauritius, corticola, 1876, Robillard (G , lectotype; G , TUR-Vainio 11453, US, isolectotypes; FH [not examined by Degelius, but probably part of the type specimen], isolectotype?). Following Degelius (1974), the lectotype (G) and the isolectotype (US) of S. robillardii are a mixture of Collema leptaleum var. leptaleum and C. cf. pulcellum var. subnigrescens. A specimen in TUR evidently belongs to the type collection and represents C. leptaleum var. leptaleum. Also reported from Pouce, Bojer (K), and Pouce, 1860, Cupes (K) (Degelius 1974: 108). nigrescens (Huds.) DC. Reported from Mauritius by Daruty (1873). robillardii (Müll. Arg.) Stizenb. =? Collema leptaleum var. leptaleum rugosum Kremp. Moka: Réduit, State House Park, on bark of Cinnamomum, 2019, Diederich Pamplemousses: 1 km NNW of Botanical Garden, S of Museum Aventure du sucre, on bark, 2016, Diederich 18624; Jardin Botanique, on bark, 2016, Diederich & Ertz Plaines Wilhems: Curepipe Botanic Gardens, on bark, 2019, Diederich & Ertz Rivière Noire: East of Black River, from Visitor s Centre to Pilgrims Trail, on bark, 2016, Diederich 18477, 18480; Chamarel, Ebony Forest, around viewpoint, on bark,

21 P. Diederich & D. Ertz: First checklist of lichens and lichenicolous fungi from Mauritius , Diederich 18556; Le Morne Peninsula, S coast, on bark, 2019, Diederich Previously reported from Pamplemousses Botanical Garden, on a tree, 1990, Hawksworth (K-IMI) by David & Hawksworth (1995), and from Moka, below Mt Ory, on a tree, 1990, Hawksworth (K-IMI) by David & Hawksworth (1995) and Crittenden et al. (1995). subflaccidum Degel. Reported from Moka, below Mt Ory, on shaded volcanic rocks, 1990, Hawksworth (K-IMI) by David & Hawksworth (1995) and Crittenden et al. (1995). A further unpublished specimen, collected in Pamplemousses Botanical Garden in 1997 by Jørgensen, is kept in BG. COLLEMOPSIDIUM Nyl. Collemopsidium mauritiae Diederich & Ertz, sp. nov. (Fig. 8) MycoBank MB Diagnosis: Distinguished by a thallus initially formed by goniocysts, eventually developing into flat areoles, a bluish green cyanobacterial photobiont, black perithecia, 180 µm diam., without involucrellum, anastomosed paraphysoids, 8-spored asci, µm, and 1-septate, hyaline ascospores, µm. Type: Mauritius, Rivière Noire, La Preneuse (between Tamarin and Grande Rivière Noire), cemetery (SE part with old graves), S, E, alt. 10 m, on old tombstones from c. 1850, 4 Aug. 2016, Diederich (MAU holotype, herb. Diederich isotype). Description. Thallus epilithic, calcicolous, crustose, greenish black to black, forming colonies up to ~5 cm diam.; when young, composed of isolate goniocysts µm diam. that become larger with age, then develop into flat, angular areoles, µm diam., µm thick (when dry), bearing marginal goniocysts as vegetative diaspores; surface of mature colonies appearing as rimose to areolate (cracks closing when thallus is wetted), matte, ± smooth to minutely uneven. Hyphal layer around goniocysts brownish when exposed, µm thick. Photobiont cyanobacterial, bluish-green, ellipsoid, 2 4-celled, µm, wall 1 2 µm thick; groups of cyanobacteria surrounded by a gelatinous sheath. Prothallus and basal layer not apparent. Ascomata perithecioid, solitary, subspherical, semi-immersed to almost superficial, slightly rough and matte, black, 180 µm diam. Ostiole sometimes depressed, µm wide when dry. Involucrellum absent. Excipulum entirely dark brown to black, µm thick; cells rather indistinct, ~6 11 µm diam. Hymenial gel I. Paraphysoids anastomosing, 1 2 µm thick. Periphysoids not observed. Asci fissitunicate, broadly ellipsoid, 8-spored, µm, at first with a broad and elongate, beak-like ocular chamber that becomes shorter and comparatively broad at maturity; ascoplasma I+ orange-red; wall I, laterally 2 3 µm, apically µm thick. Ascospores hyaline, 1-septate, slightly constricted at the septum, the upper cell slightly broader and distinctly shorter than the lower cell, µm, with a distinct hyaline perispore, 1 1.5( 2) µm thick in water. Pycnidia not observed. Ecology and distribution. On calcareous rock (mortar) in a historic cemetery, known only from the type locality in Mauritius. Notes. The genus Collemopsidium includes more than ten species worldwide (some of which formerly treated within Pyrenocollema) (Grube & Ryan 2002). Several of these are confined to marine habitats (Mohr et al. 2004), others to rocks submerged in freshwater, and a few on sand or rocks in humid conditions. Many of these are described and keyed out by Coppins & Orange (2009). Amongst the saxicolous, non-marine British species treated by those authors, C. angermannicum is distinguished by the ecology (siliceous rocks beside rivers and lakes) and the larger ascospores, µm. Both C. caesium and C. monense are as well distinguished by larger ascospores, 20 30( 33) (7.5 ) µm, resp (35) 6 8 µm. The four non-marine, mainly American species of Pyrenocollema keyed out by Harris (1995) most differ by having larger ascospores; P. atlanticum has only slightly larger ascospores but clearly differs by a yellow-brown to brown photobiont. C. montanum differs by much larger ascospores, µm, and larger ascomata, µm diam., with a distinct involucrellum (McCarthy & Kantvilas 1999). C. heardense (Øvstedal & Gremmen 2010) is distinguished by much larger ascospores, µm. C. chlorococcum is the only known species from the genus with green algae and further differs by not being saxicolous (Aptroot & van den Boom 1998). C. japonicum differs by a purplish brown, continuous thallus and larger ascospores, µm (Harada 1999). Etymology. The epithet denotes the country Mauritius (Latin: Mauritia), where the new species was discovered. Additional specimen examined. MAURITIUS. Same locality as type, 2019, Ertz 23238; Flic-en-Flac, cemetery, on historic tombs, 2019, Diederich (MAU). CONSTRICTOLUMINA Lücking, M. P. Nelsen & Aptroot planorbis (Ach.) Lücking, M. P. Nelsen & Aptroot [ Verrucaria planorbis Ach.]. Sur l écorce des Rubiacées arborescentes, à l île Maurice (Bélanger 1834). CORA Fr. ( )gyrolophia Fr., Epicr. Syst. Mycol. (Upsaliae): 556 (1838). Type: Mauritius, Sieber 65 (S L2148, lectotype, selected by Lücking et al. 2015a; HAL 3024F, isolectotype); Sieber 59 (S L39459, paratype). ( )= Gyrolophia elegans Kunze, in Von Krombholz, Naturgetr. Abbild. Beschr. Schwämme (Prague) 1: 76, tab. 5, fig. 16 (1831), nom. inval. ( )= Gyrolophia mauritianum Kunze, in Index Fungorum, nom. inval. Sieber visited Mauritius during a circumnavigation from 1822 to 1824, where he collected numerous plant specimens ( Nevertheless, it might be that these Cora specimens were not collected by him. He received many lichen specimens from the Antilles (leg. Kohaut) and from Mauritius (leg. Bojer). Possibly he obtained the Cora specimens from the Antilles but mislabelled them as Mauritius. This suggestion is supported by the statement on Wikipedia ( following which Sieber s behaviour and publications became progressively more erratic. He became more and more deranged. As the genus Cora is more or less confined to the Neotropics, with the exception of two species known from the South Atlantic islands Trindade and Saint Helena (Lücking et al. 2015a) and one described from Sri Lanka (Lücking et al. 2017b),

22 34 Plant and Fungal Systematics 65(1): 13 75, 2020 Figure 8. Collemopsidium mauritiae [holotype]. A areolate thallus; B thallus with two perithecia; C thallus with areoles (above), abundant goniocysts (below) and perithecia; D thallus developing goniocysts, in water; E cyanobacterium, in water; F group of cyanobacteria surrounded by a gelatinous sheath, in water; G section through perithecium, in water; H hymenium, showing ascus with ascospores, and paraphysoids, in Lugol; I ascospores, showing perispore, in water; J ascospores, in Lugol. Scales: A B = 200 µm; C = µm; D, G = 20 µm; H = 10 µm; E F, I J = 5 µm. Photos: P. Diederich.

23 P. Diederich & D. Ertz: First checklist of lichens and lichenicolous fungi from Mauritius 35 we prefer therefore to provisionally consider the presence of Cora gyrolophia in Mauritius as dubious, awaiting the discovery of further populations of this species either in the Antilles or in Mauritius. CORNUTISPORA Piroz. lichenicola D. Hawksw. & B. Sutton Spirographa lichenicola CROCODIA Link aurata (Ach.) Link Pseudocyphellaria aurata (Ach.) Vain.; Sticta aurata Ach. Plaines Wilhems: Curepipe, Trou aux Cerfs, along road surrounding the crater, on bark, 2016, Diederich (dupl. LG); ibid., 2019, Diederich 19203; Le Pétrin, between Pétrin Information Centre and first viewpoint along trail to the west, on bark, 2016, Diederich (MAU). Rivière Noire: Trail from Plaine Champagne towards Piton de la Petite Rivière Noire, on bark, 2016, Diederich (MAU); Chamarel, Ebony Forest, around viewpoint, on bark, 2016, Diederich Savanne: Along trail to Mt Cocotte, on bark, 2019, Diederich (MAU). Previously reported from Mauritius by Laurer (1827), Søchting 30A12 (C) by Moncada et al. (2014: 122), from Pétrin heath, Pétrin Rainforest and Le Pouce, 600 m, 2001, by Holm & Gregersen (2002), from Macchabee Forest, 1990, Hawksworth (K-IMI) by David & Hawksworth (1995) and Crittenden et al. (1995), and from Rodrigues, on trunks of trees, 1874, Balfour 2273 (BM) by Crombie (1876b) and Galloway (1994: 119). Further unpublished specimens, collected in Mt Corps de Garde and Mt Cocotte by Krog & Timdal in 1991, are kept in O. CROCYNIA (Ach.) A. Massal. gossypina (Sw.) A. Massal. Phyllopsora gossypina (Sw.) Kistenich, Timdal, Bendiksby & S. Ekman mauritiana Hue = Chrysothrix xanthina molliuscula (Nyl.) Nyl., see under Phyllopsora CYANISTICTA Gyeln. argyracea (Delise) Gyeln. Pseudocyphellaria argyracea aurigera (Bory) Dodge = Pseudocyphellaria crocata mougeotiana (Delise) Dodge = Pseudocyphellaria crocata CYPHELLOSTEREUM D. A. Reid bicolor Lücking & Timdal Willdenowia 46: 192 (2016). Type: Grand Port, Bambou Mountains, km NNE of Piton Rouge, on tree bark, 12 Nov. 1991, Krog & Timdal MAU36/02 (O L holotype, F isotype) (Lücking & Timdal 2016). DENDRISCOSTICTA B. Moncada & Lücking platyphylla (Trevis.) B. Moncada & Lücking [ Lobaria platyphylla Trevis.; Sticta damicornis var. platyphylla; = Sticta nylanderiana Zahlbr.; Stictina nylanderiana (Zahlbr.) Dodge]. This species was reported from Mauritius by Dodge (1964: 185). Specimens from Mauritius kept in S (Sieber, S F159142; n. 38 Sieber II cypt. exot. Herb. Erik P. Vrang, S F158916; Pl. crypt. exot. 38, herb. Erik P. Vrang, S F159140, S F159141) and UPS ( ad cortice arborum, Hilsenberg, Trevisan, Lichenoth. Ven. Nr. 77, Crypt. exot. exs. n. 38, UPS L696223) need to be revised. DIBAEIS Clem. holstii (Müll. Arg.) Kalb & Gierl Reported from S of Curepipe, Trou Raoul Crater, on soil, 1990, Hawksworth (K-IMI) by David & Hawksworth (1995) and Crittenden et al. (1995). DICTYONEMA C. Agardh ex Kunth album Lücking & Timdal Willdenowia 46: 192 (2016). Type: Savanne, Plaine Champagne, near viewpoint WNW of Mt Cocotte, 18 Nov. 1991, Krog & Timdal MAU57/04 (O L holotype, F, MAU 21886, isotypes) (Lücking & Timdal 2016). Also reported from the road between Mt Cocotte and Bassin Blanc, 1991, Krog & Timdal (O) (Lücking & Timdal 2016). coppinsii Lücking, Barrie & Genney Reported from Grand Port, Mt des Créoles, 1991, Krog & Timdal (F, O) by Lücking & Timdal (2016: 198). DIORYGMA Eschw. hieroglyphicum (Pers.) Staiger & Kalb Pamplemousses: Jardin Botanique, on bark of Brownea grandiflora, 2016, Ertz Port Louis and Moka: Along trail from Moka to Le Pouce, on bark, 2019, Ertz (TLC: stictic, solvents A, B ), (TLC: stictic, unknown brownish of Rf ± 20, trace of norstictic, solvents A, B ). poitaei (Fée) Kalb, Staiger & Elix [ Opegrapha poitaei (Fée) Bél.]. Sur l écorce des arbres, à l île Maurice (Bélanger 1834). DIPLOSCHISTES Norman scruposus (Schreb.) Norman Plaines Wilhems: Le Pétrin, heathland NW of Pétrin Information Centre, on lava rocks, 2016, Diederich 18363; ibid., 2019, Diederich Savanne: Road from Le Pétrin to Chamouny, beginning of trail to Montagne Cocotte, on rocks along a stream, 2016, Diederich DIRINA Fr. astridae Tehler in Tehler et al., Lichenologist 45: 444 (2013). Type: Port Louis Distr., Port Louis, Mt Signal, on the peak ~200 m E of the tele station, 2003, Tehler 8502 (S L55012, holotype; BR , isotype); ibid., Tehler 8503 (S L55013). Further reported from the western part of Mauritius (Tehler & Irestedt 2007, as Dirina paradoxa subsp. africana), from Black River, Mt St. Pierre, the eastern peak near Bambous, ~7 km E Quatre Bornes, 2003, Tehler (S) (Tehler et al. 2010, 2013; Frisch et al. 2014), and from Savanne, Maconde on south coast, ~500 m W of Baie du Cap, 2003, Tehler (S) (Tehler et al. 2013). monothalamia Tehler & Ertz. The Mauritius material published under this name by Frisch et al. (2014) belongs to Dirina astridae Tehler (Tehler et al. 2013). paradoxa subsp. africana (Fée) Tehler. The Mauritius material published under this name by Tehler & Irestedt (2007) belongs to Dirina astridae Tehler (Tehler et al. 2013).

24 36 Plant and Fungal Systematics 65(1): 13 75, 2020 DIRINARIA (Tuck.) Clem. aegialita (Afzel. ex Ach.) B. J. Moore Physcia aegialita (Afzel. ex Ach.) Nyl. Moka: Réduit, State House Park, on bark of Pinus, 2019, Diederich 19318; Réduit, close to Mauritius Herbarium building, on bark of Mangifera, 2019, Diederich 18690; ibid., on bark of Pinus, Diederich Plaines Wilhems: Curepipe, Curepipe Botanic Gardens, on bark, 2016, Diederich 18304; ibid., on bark of palm trees, 2019, Diederich & Ertz (TLC of 24206: atranorin, divaricatic, unknown terpenes, solvents A, B ). Rivière Noire: Trail from Plaine Champagne towards Piton de la Petite Rivière Noire, on bark, 2019, Ertz (TLC: atranorin, divaricatic, unknown terpenes, solvents A, B ). Previously reported from Nicolière Mountains, Nouvelle Découverte, on volcanic rocks, 1990, Hawksworth (K-IMI) by David & Hawksworth (1995) and Crittenden et al. (1995), and from Rodrigues, on rocks, 1874, Balfour 2225 by Crombie (1876b). A further unpublished specimen, collected in Réduit near the Mauritius Herbarium by Krog & Timdal in 1991, is kept in O. applanata (Fee) D. D. Awasthi Moka: Réduit, State House Park, on bark of Cinnamomum, 2019, Diederich 19313; ibid., on bark of Pinus, 2019, Diederich Pamplemousses: 1 km NNW of Botanical Garden, S of Museum Aventure du sucre, on bark, 2016, Diederich Rivière Noire: La Preneuse (between Tamarin and Grande Rivière Noire), cemetery (SE part with old graves), on bark at the base of a tree, 2016, Diederich 18386; Chamarel, Ebony Forest, around viewpoint, on exposed rocks, 2019, Diederich Previously reported from Mauritius by Crittenden et al. (1995), from centre de Flacq, on Ficus, 1990, Hawksworth (K-IMI) by David & Hawksworth (1995), and from Pamplemousses Botanical Garden, on Hyophorbe amaricaulis, 1990, Hawksworth (K-IMI) by David & Hawksworth (1995). picta (Sw.) Schaer. ex Clem. Physcia picta (Sw.) Nyl. Moka: Réduit, State House Park, on bark, 2019, Diederich 19290; Réduit, close to Mauritius Herbarium building, on bark of Pinus, 2019, Diederich Pamplemousses: Jardin Botanique, on bark, 2016, Diederich 18240, 18268, Rivière Noire: Chamarel, Ebony Forest, around viewpoint, on exposed rocks, 2019, Diederich Previously reported from Mauritius by Lindau (1908), from Round Island, on W side of the island by Johnston (1894: 263), from Ile aux Aigrettes by Parnell et al. (1989) (BM, det. James), and from Rodrigues, on branches of trees, 1874, Balfour 2373 by Crombie (1876b). DYPLOLABIA A. Massal. afzelii (Ach.) A. Massal. [ Graphis afzelii Ach.]. Reported from Mauritius by Daruty (1873) and Crittenden et al. (1995). ENDOCARPON Hedw. johnstonii (Müll. Arg.) Stizenb. Ber. Thätigk. St. Gallischen Naturwiss. Ges : 259 (1895); Paracarpidium johnstonii Müll. Arg., Hedwigia 31: 286 (1892). Type: Ile aux Fouquets, Mauritius, vulgaris ad saxa sabulosa, ~5 35 ped. supra mare, Johnston (G holotype, BM isotype). ERIODERMA Fée sorediatum D. J. Galloway & P. M. Jørg. Reported from Piton de la Petite Rivière Noire by Timdal (2002: 296), and from the entrance to Macchabee Forest, on bark, 1990, Hawksworth (K-IMI) by David & Hawksworth (1995) and Crittenden et al. (1995). Further unpublished specimens from Plaine Champagne towards Piton de la Petite Rivière Noire and Mt Cocotte, collected by Krog & Timdal in 1991, are kept in O. ETAYOA Ertz & Diederich +trypethelii (Flakus & Kukwa) Diederich & Ertz Plaines Wilhems: Curepipe, Trou aux Cerfs, along road surrounding the crater, on bark, on Phaeographis, 2016, Diederich (sub Phaeographis sp.); Le Pétrin, between Pétrin Information Centre and first viewpoint along trail to the west, on bark, on Allographa calcea, 2016, Diederich (sub A. calcea); Le Pétrin, heathland NW of Pétrin Information Centre, on bark, on Graphidaceae, 2019, Diederich This lichenicolous fungus is rather common in tropical and subtropical countries, where it can be found on corticolous, crustose lichens belonging to different phylogenetic groups, being particularly frequent on members of Graphidales (Ertz et al. 2014). FLAVOPARMELIA Hale caperata (L.) Hale [ Parmelia caperata (L.) Ach.]. Reported from Mauritius by Daruty (1873), and Sur les arbres, à l île Maurice by Bélanger (1834) (PC ). GIBBOSPORINA Elvebakk, S. G. Hong & P. M. Jørg. didyma Elvebakk, Hong & P. M. Jørg. Reported from Piton de la Petite Rivière Noire, 1991, Krog & Timdal (O) by Elvebakk et al. (2016: 32). mascarena Elvebakk, Hong & P. M. Jørg. Rivière Noire: Trail from Plaine Champagne towards Piton de la Petite Rivière Noire, on bark, 2016, Diederich (dupl. LG); ibid., 2019, Ertz 23915, Savanne: Along trail to Mt Cocotte, on bark, 2019, Diederich Previously reported from the same two localities and from Macchabee Forest, 1991, Krog & Timdal (O) by Elvebakk et al. (2016: 35). GLOMERULOPHORON Frisch, Ertz & G. Thor mauritiae Frisch, Ertz & G. Thor in Frisch et al., Lichenologist 47: 252 (2015). Type: Mauritius, Pamplemousses, Botanical Garden, parc, sur tronc, 18 Febr. 2014, Ertz (BR holotype, MAU isotype). Moka: Réduit, State House Park, on bark, 2019, Diederich 18731, 18738; Réduit, close to Mauritius Herbarium, on bark, 2019, Diederich Pamplemousses: Same locality as type, on bark, 2016, Diederich Rivière Noire: Chamarel, Ebony Forest, along trail W of viewpoint,

25 P. Diederich & D. Ertz: First checklist of lichens and lichenicolous fungi from Mauritius 37 on bark, 2019, Diederich 19447; Le Morne Peninsula, S coast, on bark, 2019, Diederich & Ertz Currently known from Mauritius and Seychelles (Diederich et al. 2017). GLYPHIS Ach. cicatricosa Ach. = G. cicatricosa var. favulosa (Ach.) Nyl.; = G. cribrosa Fée Moka: Réduit, State House Park, on bark, 2019, Diederich 19286; ibid., on bark of Terminalia angustifolia, 2019, Diederich Pamplemousses: Jardin Botanique, on bark of Verschaffeltia splendens, 2016, Ertz 21433; ibid., on bark of Agathis, Ertz Plaines Wilhems: Plaisance, Rose Hill, sur un Jam Rosadier (Syzygium jambos), s. d. (probably 1873 or 1874), Daruty 63 (MAU L1995!, sub Verrucaria nitida); Curepipe Botanic Gardens, on bark, 2019, Diederich 19137, & Ertz 24182; Le Pétrin, along trail W of Pétrin Information Centre, up to 600 m W of first viewpoint, on bark, 2019, Diederich & Ertz Rivière Noire: East of Black River, from Visitor s Centre to Pilgrims Trail, on bark, 2016, Diederich Reported from Mauritius by Daruty (1873, as G. cicatricosa and G. cribrosa), and from Rodrigues, on branches of trees, 1874, Balfour 2295 by Crombie (1876b, as G. cicatricosa var. favulosa). cicatricosa var. favulosa (Ach.) Nyl. = Glyphis cicatricosa cribrosa Fée = Glyphis cicatricosa scyphulifera (Ach.) Staiger Moka: Réduit, State House Park, on bark of Phyllanthus emblica, 2019, Diederich Pamplemousses: Jardin Botanique, on bark of Dypsis lutescens, 2016, Ertz tricosula Nyl. ex Cromb. Sarcographa tricosula GRAPHIS Adans. aequabilis Wedd. ex Nyl. Phaeographis aequabilis afzelii Ach. Dyplolabia afzelii alboglaucescens Adaw. & Makhija Pamplemousses: Jardin Botanique, on bark of Agathis, 2016, Ertz analoga Nyl. Reported from Rodrigues, on bark of trees, 1874, Balfour 2218, by Crombie (1876b). anfractuosa (Eschw.) Eschw. Reported from Mauritius by Daruty (1873). anguina (Mont.) Nyl. Reported from Mauritius by Daruty (1873). angustata Eschw. Allographa angustata assimilis Nyl. Reported from Rodrigues, on bark of trees, 1874, Balfour 2312, by Crombie (1876b). cincta (Pers.) Aptroot Pamplemousses: Jardin Botanique, on bark of Agathis, 2016, Ertz comma (Ach.) Spreng. Allographa comma contexta (Pers.) Nyl. Reported from Mauritius by Daruty (1873). duplicata Ach. Opegrapha duplicata (Ach.) Bél. Port Louis and Moka: Along trail from Moka to Le Pouce, on bark, 2019, Ertz 24106, This species was reported by Bélanger (1834) Sur l écorce des arbres, dans la péninsule indienne, aux îles Maurice et de Bourbon. gomphospora Müll. Arg. J. Linn. Soc., Bot. 30: 458 (1895). Type: Mauritius, Pic du Pouce (G ). This species belongs to Fissurina ( but has not yet formally been transferred there. librata C. Knight Reported from Moka, below Mt Ory, 200 m, on a shaded tree, 1990, Hawksworth (K-IMI) by David & Hawksworth (1995) and Crittenden et al. (1995). pallescens Vain. Reported from Moka, Nouvelle Découverte, 3 km N of village, 300 m, on bark, 1990, Hawksworth (K-IMI) by David & Hawksworth (1995) and Crittenden et al. (1995). pulverulenta (Pers.) Ach. [ Graphis scripta var. pulverulenta (Pers.) Ach.]. Reported from Mauritius by Daruty (1873). pyrrhocheiloides Zahlbr. Pamplemousses: Jardin Botanique, on bark of Verschaffeltia splendens, 2016, Ertz rugulosa (Fée) Spreng. [ Opegrapha rugulosa Fée]. Sur l écorce des arbres, à l île Maurice (Bélanger 1834). scalpturata Ach. Phaeographis scalpturata scripta (L.) Ach. Reported from Mauritius by Daruty (1873). scripta var. pulverulenta (Pers.) Ach. Graphis pulverulenta turgidula Müll. Arg. = Allographa rustica uniformis Fée. Reported from Mauritius by Daruty (1873). GYALECTA Ach. tropica Bél., Voyage aux Indes-orientales, pendant les années : 127 (1834). Type: Sur l écorce des arbres, à l île Maurice (PC ) (Bélanger 1834). GYALECTIDIUM Müll. Arg. filicinum Müll. Arg. Reported from Mauritius, foliicolous on Acrostichum obductum (S) by Santesson (1952: 358). GYALOLECHIA A. Massal. bassiae (Ach.) Søchting, Frödén & Arup ex Ahti Caloplaca bassiae (Ach.) Zahlbr. = Lecanora aurantiaca var. isidiosella Cromb., Journ. Linn. Soc., Bot. 15: 437 (1876); Caloplaca isidiosella (Cromb.) R. Sant., in Moberg, Thunbergia 5: 3 (1987). Type:

26 38 Plant and Fungal Systematics 65(1): 13 75, 2020 Rodrigues, on the bark of trees, 1874, Balfour 2211 (BR , isotype; BM, syntypes) (Crombie 1876b). Moka: Réduit, State House Park, on bark, 2019, Diederich Further reported from Mauritius, Søchting 9748 (C) by Arup et al. (2013), and from Pamplemousses Botanical Garden, 1990, Hawksworth (K-IMI) by David & Hawksworth (1995) and Crittenden et al. (1995). Wetmore (2004: 289) included L. aurantiaca var. isidiosella in the synonymy of G. bassiae and stated that he did not find the type specimen (Balfour 2336) in BM. However, the type of var. isidiosella is specimen Balfour 2211, while specimen Balfour 2336 was published as Lecanora aurantiaca by Crombie (1876b), a name currently considered a synonym of Gyalolechia flavorubescens. flavorubescens Søchting, Frödén & Arup [= Lecanora aurantiaca (Lightf.) Flot.]. Reported from Rodrigues, on bark of trees, 1874, Balfour 2336, by Crombie (1876b). HAEMATOMMA A. Massal. africanum (Steiner) Dodge Rivière Noire: Trail from Plaine Champagne towards Piton de la Petite Rivière Noire, on branches of a tree, 2016, Diederich Previously reported from Rodrigues, on bark of trees, 1874, Balfour 2238 (BM) by Staiger & Kalb (1995). New for the island of Mauritius. collatum (Stirton) Dodge Reported from Mauritius, Plains, 1857, Ayres (BM), 1873, Weddell (H), and 1867 (BM-Hooker) by Staiger & Kalb (1995). persoonii (Fée) A. Massal. Reported from Mauritius, 1860, Ayres (BM) by Staiger & Kalb (1995). puniceum (Sw.) A. Massal. [ Lecanora punicea (Sw.) Ach.; Parmelia punicea (Sw.) Ach.]. Reported from Mauritius (Daruty 1873), from Rodrigues, 1874, Balfour 2238 (Crombie 1876b), and Sur l écorce des arbres, aux îles Maurice et de Java (PC ) (Bélanger 1834). The report from Rodrigues refers to H. africanum; the two other reports are almost surely erroneous, as H. puniceum is a rare species known only from Peru (Staiger & Kalb 1995). HEPPIA Nägeli ex A. Massal. rodriguesii Cromb. Peltula rodriguesii HETERODERMIA Trevis. comosa (Eschw.) Follmann & Redón [ Anaptychia comosa (Eschw.) A. Massal.]. Reported from Mauritius, auf Ästen by Lindau (1908). hypoleuca (Mühl.) Trevis. Polyblastidium hypoleucum japonica (Satō) Swinscow & Krog Polyblastidium japonicum obscurata (Nyl.) Trevis. Port Louis and Moka: Along trail from Moka to Le Pouce, on rock, 2019, Ertz (TLC: atranorin, zeorin, cf 16ß-acetoxyhopane-6α,22-diol, cf. 7-chloroemodin, solvent A). Rivière Noire: Chamarel, Ebony Forest, around viewpoint, on rock, 2019, Ertz (TLC: atranorin, zeorin, cf 16ß-acetoxyhopane-6α,22-diol, cf. 7-chloroemodin, solvent A). Previously reported from Mauritius by Crittenden et al. (1995). A further unpublished specimen, 1874, Balfour is kept in E. speciosa (Wulfen) Trevis. [ Anaptychia speciosa (Wulfen) A. Massal.; Physcia speciosa (Wulfen) Nyl.]. Reported from Mauritius by Daruty (1873) and Lindau (1908), and from Rodrigues, on trees and rocks, 1874, Balfour 2289, 2324, by Crombie (1876b). HYPERPHYSCIA Müll. Arg. adglutinata (Flörke) H. Mayrh. & Poelt Moka: Réduit, State House Park, on bark, 2019, Diederich & Ertz 23254; ibid., on bark of Ficus microcarpa, 2019, Diederich Pamplemousses: 1 km NNW of Botanical Garden, S of Museum Aventure du sucre, on bark, 2016, Diederich 18510, 18621; Jardin Botanique, on twigs, 2016, Diederich Rivière Noire: Chamarel, near Seven Coloured Earths, on branches, 2016, Diederich 18627; Le Morne Peninsula, S coast, on bark, 2019, Diederich A further unpublished specimen, collected by Jørgensen in Pamplemousses in 1997, is kept in BG (L 34990). New for Mauritius. HYPOGYMNIA (Nyl.) Nyl. inflata Dodge, Ann. Missouri Bot. Gard. 46: 47 (1959). Type: Mauritius, growing with hepatics (BM). HYPOTRACHYNA (Vain.) Hale microblasta (Vain.) Hale = Parmelia mauritiana Gyeln., Repert. Spec. Nov. Regni Veg. 29: 288/416 (1931b), nom. nov. for P. caraccensis f. isidiosa; Pseudevernia mauritiana (Gyeln.) Dodge, Ann. Missouri Bot. Gard. 46: 182 (1959); Parmelia caraccensis f. isidiosa Müll. Arg., Flora 74: 376 (1891). Type: Mauritius (K, holotype; BM , isotype; G , isotype) (Hale 1968, 1971: 18). Also reported from Macchabee Forest, 1990, Hawksworth (K-IMI) by David & Hawksworth (1995) and Crittenden et al. (1995), and from road between Mt Cocotte and Bassin Blanc, 1991, Krog & Timdal (O) by Lücking & Timdal (2016: 194). Further unpublished specimens from Piton de la Petite Rivière Noire, Curepipe (Trou aux Cerfs) and Mt Cocotte, collected by Krog in Timdal in 1991, are kept in O. JULELLA Fabre geminella (Nyl.) R. C. Harris Rivière Noire: Chamarel, Ebony Forest, close to park buildings, on bark, 2016, Diederich KROGIA Timdal coralloides Timdal Lichenologist 34: 293 (2002). Type: Black River, along path from Plaine Champagne towards Piton de la Petite Rivière Noire, 15 Nov. 1991, Krog & Timdal MAU51/83

27 P. Diederich & D. Ertz: First checklist of lichens and lichenicolous fungi from Mauritius 39 (O-L-21909, holotype); ibid., Krog & Timdal MAU51/80 (O-L-21908, BM, M, UPS, paratypes) (Timdal 2002, Kistenich et al. 2018: 903). Rivière Noire: Trail from Plaine Champagne towards Piton de la Petite Rivière Noire, on bark, 2016, Diederich (det. Timdal). LECANOGRAPHA Egea & Torrente subnothella (Nyl.) Ertz Pamplemousses: Sir Seewoosagur Ramgoolam Botanical Garden, on bark, 2014, Ertz 19162; ibid., on bark of Terminalia, 2016, Ertz In specimen Ertz 21447, most of the lirellae have a whitish pruina, but others are yellowish pruinose, showing that this species might, surprisingly, have two types of pruina. New for Mauritius. LECANORA Ach. achroa Nyl. ex Cromb. J. Bot. 14: 263 (1876). Type: Rodrigues, on bark of trees, 1874, Balfour 2311 (H-NYL 27475, lectotype, selected by Lumbsch & Feige 1995; H-NYL 27293, isolectotype; E, isolectotype?) (Crombie 1876a, b; Lumbsch et al. 1995; Papong & Lumbsch 2011). = achroella Nyl. ex Cromb., J. Bot. 14: 263 (1876). Type: Rodrigues, on bark of trees, 1874, Balfour 2255 (H-NYL 27135, holotype) (Crombie 1876a, b; Lumbsch et al. 1995). = subflavicans Nyl. ex Cromb., J. Bot. 14: 264 (1876). Type: Rodrigues, corticole, on bark of trees, 1874, Balfour 2223 (H-NYL 27287, holotype) (Crombie 1876a, b; Lumbsch et al. 1995). A rather common, corticolous, pantropical species (Lumbsch et al. 1995). achroella Nyl. ex Cromb. = Lecanora achroa albella (Pers.) Ach. Reported from Mauritius by Daruty (1873). allophana (Ach.) Nyl. [ Lecanora subfusca var. allophana Ach.]. Reported from Mauritius by Daruty (1873). apostatica Nyl. ex Cromb. Loekoesia apostatica apostatica var. obliquans Nyl. ex Cromb. = Loekoesia apostatica argentata (Ach.) Malme [ Lecanora subfusca var. argentata Ach.]. Reported from Mauritius by Daruty (1873). atra (Hudson) Ach. Tephromela atra atra f. succedanea Nyl. =? Tephromela atra (Huds.) Hafellner aurantiaca (Lightf.) Flot. = Gyalolechia flavorubescens aurantiaca var. isidiosella Cromb. = Gyalolechia bassiae aurantiella Nyl. ex Cromb. Caloplaca aurantiella campestris (Schaer.) Hue. Reported from Mauritius by Crittenden et al. (1995). caesiorubella Ach. Reported from Mauritius by Daruty (1873). carneofusca Nyl. ex Cromb. Caloplaca diplacia var. carneofusca cinnabarina Ach. Brownliella cinnabarina coniopta Nyl. = Rinodina luridescens conizaea (Ach.) Nyl. Reported from Rodrigues, on decorticated trunks, 1874, Balfour 2335 by Crombie (1876b). conizopta Nyl. ex Cromb., J. Bot. 14: 263 (1876). Type: Rodrigues, corticole (Crombie 1876a) or on rocks (Crombie 1876b) [photos on JSTOR suggest rocks], 1874, Balfour 2217 (H-NYL 26146, holotype [fide Lumbsch 1994: 156]; M, isotype) (Crombie 1876a, b). glaucofuscula Nyl. ex Cromb. Caloplaca glaucofuscula glaucofuscula f. biatoroidea Cromb., see under Caloplaca leucoxantha Müll. Arg. Reported from Rodrigues, on bark of trees, 1874, Balfour 2366, by Crombie (1876b). muralis (Schreb.) Rabenh. Reported from Mauritius by Riedl & Riedl-Dorn (1986). murorum (Hoffm.) Ach. Reported from Mauritius by Hue (1892: 128). murorum var. lobulata (Sommerf.) Schaer. Bilimbia lobulata oreinoides (Körb.) Hertel & Rambold =? Lecidea melopta Nyl. ex Cromb., J. Bot. 14: 264 (1876). Type: Rodrigues, on rocks, 1874, Balfour 2281 (E, G, H, UPS L076078) (Crombie 1876a, b). Following the type of Lecidea melopta in E belongs to L. oreinoides. parella var. pallescens (L.) Ach. Ochrolechia pallescens parella var. phloeoleuca Nyl. = Ochrolechia africana perlutescens Nyl. ex Cromb., J. Bot. 14: 263 (1876). Type: Rodrigues, on bark of trees, 1874, Balfour 2222 (H-NYL 26299) (Crombie 1876a, b). punicea (Sw.) Ach. Haematomma puniceum sorediifera Fée [ Parmelia sorediifera (Fée) Bél.]. Sur les écorces d arbres, à l île Maurice (Bélanger 1834). subflavicans Nyl. ex Cromb. = Lecanora achroa subfusca (L.) Ach. Reported from Mauritius, Round Island, on west side of the island, on dead branches of Fernelia buxifolia, 200 ft by Johnston (1894: 263). subfusca [ subfurea ] var. allophana [ allofara ] Ach. Lecanora allophana subfusca [ subfurea ] var. argentata Ach. Lecanora argentata subfusca f. pumicicola Nyl., in Crombie, Journ. Linn. Soc., Bot. 15: 438 (1876). Type: Rodrigues, on rocks, 1874, Balfour 2296, 2299 (M, type?; UPS L106912, in database sub Lecanora pseudistera) (Crombie 1876b). sulphureofusca Fée Sipmaniella sulphureofusca vigilans Taylor = Megalospora coccodes subsp. coccodes LECIDEA Ach. achroopholis Nyl. ex Cromb., J. Bot. 14: 264 (1876); Psora achroopholis (Nyl. ex Cromb.) C. W. Dodge, Beih. Nova Hedwigia 12: 230 (1964). Type: Rodrigues, on rocks, 1874, Balfour 2272 (E, H-NYL 13024) (Crombie 1876a, b). canorubella Nyl. Reported from Mauritius by Daruty (1873). coccocarpioides Nyl. ex Cromb. Rolfidium coccocarpoides compacta Nyl. Phyllopsora compacta

28 40 Plant and Fungal Systematics 65(1): 13 75, 2020 configurans Nyl. ex Cromb., J. Bot. 14: 264 (1876). Type: Rodrigues, on rocks, 1874, Balfour 2224 (E, H) (Crombie 1876a, b). continens Nyl. ex Cromb. Buellia continens disciformis Nyl. Reported from Mauritius by Daruty (1873) and from Rodrigues, on bark of trees, 1874, Balfour 2331, by Crombie (1876b). immutans Nyl. ex Cromb. Buellia immutans leucoxantha var. bispora Nyl., Mém. Soc. Imp. Sci. Nat. Cherbourg 5: 123 (1857), nom. nud. (description missing). Original material: Guyan., ins. Maurit.. leucoxantha var. ochrocarpa Nyl., Mém. Soc. Imp. Sci. Nat. Cherbourg 5: 123 (1857), nom. nud. (description missing). Original material: Ins. Maurit.. mauritiana Taylor Phyllopsora mauritiana megacarpa Nyl. = Megalospora sulphurata megaspora Leight. = Megalospora sulphurata melopta Nyl. ex Cromb. =? Lecanora oreinoides mutabilis Fée. Reported from Mauritius by Daruty (1873). spuria Schaer. Buellia spuria triphragmia Nyl. = Buellia geophila tuberculosa Fée Megalospora tuberculosa vulpina Tuck. Letrouitia vulpina LEIODERMA Nyl. erythrocarpum (Nyl.) D. J. Galloway & P. M. Jørg. Rivière Noire: Trail from Plaine Champagne towards Piton de la Petite Rivière Noire, on bark, 2019, Ertz Savanne: Along trail to Mt Cocotte, on bark, 2019, Diederich & Ertz 23508, Also reported from Piton de la Petite Rivière Noire by Timdal (2002: 296), from Curepipe, 1933, Vaughan (BM), Plaine Champagne, 20 km S of Rose Hill, 1979, Arvidsson & Nilsson (GB), Plaine Raoul, 15 km S of Rose Hill, 1979, Arvidsson & Nilsson (GB) by Galloway & Jørgensen (1987), from entrance to Macchabee Forest, 1990, Hawksworth (K-IMI) by David & Hawksworth (1995) and Crittenden et al. (1995), and from road between Mt Cocotte and Bassin Blanc, 1991, Krog & Timdal (O) by Lücking & Timdal (2016: 194). Further unpublished specimens from the Macchabee Forest, Le Pouce and Mt Cocotte, collected by Krog & Timdal in 1991, are kept in O. LEPIDOCOLLEMA Vain. brisbanense (C. Knight) P. M. Jørg. =? Pannaria rubiginosa var. dispartita Nyl., in Crombie, J. Linn. Soc. (Bot.) 15: 436 (1876b); P. dispartita (Nyl.) Vain. Type: Rodrigues, on rotten stumps on the ground, 1874, Balfour (BM, lectotype, selected by Jørgensen 2003). Plaines Wilhems: Curepipe, Curepipe Botanic Gardens, on bark, 2016, Diederich (dupl. LG); Le Pétrin, heathland NW of Pétrin Information Centre, on bark, 2019, Diederich 18832; Le Pétrin, between Pétrin Information Centre and first viewpoint along trail to the west, on bark, 2016, Diederich (dupl. LG), Rivière Noire: Trail from Plaine Champagne towards Piton de la Petite Rivière Noire, on bark, 2016, Diederich (dupl. LG), (dupl. LG), 18446; east of Black River, from Visitor s Centre to Pilgrims Trail, on bark, 2016, Diederich (MAU), 18495, (dupl. LG), (dupl. LG), (dupl. LG). Following Jørgensen (2003), the type of Pannaria rubiginosa var. dispartita belongs to Parmeliella stylophora s.lat.. As the distinction between Lepidocollema stylophorum (Vainio) P. M. Jørg. and L. brisbanense needs further investigation [Jørgensen (2000) even suggested that the mainly neotropical L. stylophorum may be a later synonym of L. brisbanense], we have provisionally included all isidiate specimens in L. brisbanense. marianum (Fr.) P. M. Jørg. = Pannaria luridula Nyl. ex Cromb., J. Bot. 14: 263 (1876). Type: Rodrigues, on the ground, 1874, Balfour 2208 (H- NYL 31278, holotype) (represents L. marianum, det. Jørgensen 2002) (Crombie 1876a, b). Further unpublished specimens from Mt Cocotte, collected by Krog & Timdal in 1991, are kept in O. LEPRA Scop. amara (Ach.) Hafellner Rivière Noire: Trail from Plaine Champagne towards Piton de la Petite Rivière Noire, on bark, 2016, Diederich 18397, (det. Kukwa; TLC: picrolichenic). This is a surprising discovery of a mainly temperate species. LEPRARIA Ach. arbuscula (Nyl.) Lendemer & B. P. Hodk. Stereocaulon arbuscula Nyl.; Leprocaulon arbuscula (Nyl.) Nyl. Reported from Mauritius, 1869, Peck (CAN, FH) (Lamb 1966, Lamb & Ward 1974: 518). cf. elobata Tønsberg Rivière Noire: Chamarel, Ebony Forest, along trail to viewpoint, ~50 m before viewpoint, terricolous, on vertical banks of road protected from rain, 2016, Diederich (det. Kukwa; dupl. UGDA). Following Kukwa (pers. comm.), this specimen is very close to Lepraria elobata. It has small, more or less regular greyish granules and lacks projecting hyphae, typical for this species; however, the granules are a bit smaller than in typical specimens and form a really thick layer, which is rather atypical for L. elobata. Although the entire variation of the species may not be known, especially in the tropics, it is possible that the examined specimen is old, resulting in a relatively thick layer of granules. finkii (B. de Lesd.) R. C. Harris Plaines Wilhems: Curepipe, Curepipe Botanic Gardens, on bark, 2016, Diederich 18295, 18310; ibid., 2019, Diederich 19152; Le Pétrin, along trail W of Pétrin Information Centre, up to 600 m W of first viewpoint, on bark, 2019, Diederich Rivière Noire: Trail from Plaine Champagne towards Piton de la Petite Rivière Noire, on bark, 2016, Diederich 18397, 18403; Brise Fer Forest, on bark, 2019, Diederich (all det. Kukwa dupl. UGDA).

29 P. Diederich & D. Ertz: First checklist of lichens and lichenicolous fungi from Mauritius 41 flava (Willd.) Ach. = Chrysothrix candelaris pallida Sipman Rivière Noire: Trail from Plaine Champagne towards Piton de la Petite Rivière Noire, on bark, 2016, Diederich (det. Kukwa; TLC: atranorin, zeorin, fatty ac.). LEPROCAULON Nyl. arbuscula (Nyl.) Nyl. Lepraria arbuscula LEPTOGIUM (Ach.) Gray azureum (Sw.) Mont. Collema azureum (Sw.) Ach.; Leptogium tremelloides var. azureum (Sw.) Nyl. Plaines Wilhems: Curepipe, Curepipe Botanic Gardens, on bark, 2016, Diederich 18306; ibid., 2019, Diederich 19099, Port Louis and Moka: Along trail from Moka to Le Pouce, on bark, 2019, Ertz Rivière Noire: Trail from Plaine Champagne towards Piton de la Petite Rivière Noire, on bark, 2016, Diederich 18449; ibid., 2019, Ertz 23919; east of Black River, from Visitor s Centre to Pilgrims Trail, on bark, 2016, Diederich 18479; Chamarel, Ebony Forest, around viewpoint, on bark, 2016, Diederich 18555; ibid., along trail W of viewpoint, on bark, 2019, Diederich 18944, 18947, & Ertz Savanne: Along trail to Mt Cocotte, on bark, 2019, Diederich & Ertz Previously reported from Mauritius by Daruty (1873) by Crittenden et al. (1995), and Sur l écorce des arbres, dans les lieux humides des forêts by Bélanger (1834) (PC ). burgessii (L.) Mont. [ Collema burgessii (L.) Ach.] Sur les arbres, dans les forêts des îles Maurice et de Java (Bélanger 1834). cyanescens (Rabenh.) Körb. Plaines Wilhems: Curepipe, Curepipe Botanic Gardens, on bark, 2016, Diederich Rivière Noire: Trail from Plaine Champagne towards Piton de la Petite Rivière Noire, on bark, 2016, Diederich 18415, 18439; ibid., 2019, Ertz 23920; east of Black River, from Visitor s Centre to Pilgrims Trail, on bark, 2016, Diederich 18475; Chamarel, Ebony Forest, around viewpoint, on bark, 2016, Diederich 18552, & Ertz 23565; ibid., along trail W of viewpoint, on bark, 2019, Diederich 18933, & Ertz 23580, p.p. Le Morne Peninsula, S coast, on bark, 2019, Ertz Savanne: Along trail to Mt Cocotte, on bark, 2019, Diederich Also reported from Mauritius by Crittenden et al. (1995) and from Ile aux Aigrettes by Parnell et al. (1989) (BM, det. James). fuliginellum Wedd., in Daruty, Trans. Roy. Soc. Arts Mauritius, n.s. 7: 164 (1873), nom. nud. (description missing). marginellum (Sw.) Gray Collema marginellum (Sw.) Raeusch. Port Louis and Moka: Along trail from Moka to Le Pouce, on bark, 2019, Ertz Rivière Noire: Chamarel, Ebony Forest, around viewpoint, on bark, 2016, Diederich 18550; ibid., along trail W of viewpoint, on bark, 2019, Diederich & Ertz Previously reported from Mauritius by Bélanger (1834) (PC ). An unpublished specimen from Le Pouce, collected by Krog & Timdal in 1991, is kept in O. mastocheilum (Vain.) Kitaura & Marcelli Rivière Noire: Chamarel, Ebony Forest, around viewpoint, on bark, 2016, Diederich 18551; ibid., along trail W of viewpoint, on bark, 2019, Diederich 18924, & Ertz 23611; trail from Plaine Champagne towards Piton de la Petite Rivière Noire, on bark, 2016, Diederich phyllocarpum (Pers.) Mont. Reported from Mauritius by Daruty (1873). tremelloides (L. f.) Gray. Reported from Mauritius by Daruty (1873) and Lindau (1908), 1889, fr. Rodriguez by Hue (1898: 223), and from Rodrigues, on trunks of trees, 1874, Balfour 2201, by Crombie (1876b). tremelloides var. azureum Nyl. Leptogium azureum tremelloides var. rugulosum Nyl. Reported In ins. Mauritii, sur les rochers humides et les arbres, à Plaisance, près de Rose-Hill, Daruty 90, 30 mai 1873 by Hue (1898). LETROUITIA Hafellner & Bellem. vulpina (Tuck.) Hafellner & Bellem. Lecidea vulpina Tuck. Rivière Noire: Trail from Plaine Champagne towards Piton de la Petite Rivière Noire, on bark, 2016, Diederich 18420; Chamarel, Ebony Forest, along trail W of viewpoint, on bark of Diospyros tessellaria, 2019, Diederich Previously reported from Mauritius by Hue (1892: 200), ex herb. Hooker (H-NYL 18038) by Hafellner (1981: 718), and from Brise de Fer, 2001, Søchting (C) and Le Pouce, 2001, Søchting (C) by Johannson et al. (2005: 148). LEUCODERMIA Kalb leucomelos (L.) Kalb [ Anaptychia leucomelaena (L.) A. Massal.]. Reported from Mauritius by Lindau (1908). LICHEN L. floridus L. Usnea florida roccella L. The report from Mauritius by Flörke (1809) probably refers to Roccella boryi. LICHENOPELTELLA Höhn. +ramalinae Etayo & Diederich Rivière Noire: Trail from Plaine Champagne towards Piton de la Petite Rivière Noire, 2016, on bark, on Ramalina sprengelii, Diederich This lichenicolous ascomycete, confined to Ramalina hosts, is new for Mauritius. LOBARIA (Schreb.) Hoffm. holstiana (Müll. Arg.) Zahlbr. Reported from Le Pouce, 600 m, 2001, by Holm & Gregersen (2002). Further unpublished specimens from Plaine Champagne towards Piton de la Petite Rivière Noire and Mt Corps de Garde, collected by Krog & Timdal in 1991, are kept in O.

30 42 Plant and Fungal Systematics 65(1): 13 75, 2020 patinifera (Taylor) Hue Reported from Mt des Créoles, 1991, Krog & Timdal (MAU, O) by Lücking & Timdal (2016: 198). Further unpublished specimens from Le Pouce, Piton de la Petite Rivière Noire, Mt Corps de Garde and Macchabee Forest, collected by Krog & Timdal in 1991, are kept in O. pulmonaria (L.) Hoffm. [= Sticta pulmonacea (Ach.) Ach.]. Reported from Mauritius by Laurer (1827). retigera (Bory) Trevis. Rivière Noire: Trail from Plaine Champagne towards Piton de la Petite Rivière Noire, on bark, 2016, Diederich (dupl. LG). Savanne: Along trail to Mt Cocotte, on bark, 2019, Diederich 18853, Previously reported from Mauritius by Lindau (1908) and from le Pouce, 600 m, 2001, by Holm & Gregersen (2002). Further unpublished specimens from Le Pouce, Plaine Champagne towards Piton de la Petite Rivière Noire, Grand Bassin and Mt Cocotte, collected by Krog & Timdal in 1991, are kept in O. wightii Dodge = Ricasolia sublaevis LOBARIELLA Yoshim. crenulata (Hook. f.) Yoshim. [ Parmelia crenulata Hook f.]. Sur l écorce des arbres, à l île Maurice (Bélanger 1834). LOEKOESIA S. Y. Kondr., S.-O. Oh & Hur Loekoesia apostatica (Nyl. ex Cromb.) Ertz & Diederich, comb. nov. (Figs 9 10) MycoBank MB Basionym: Lecanora apostatica Nyl. ex Cromb., J. Bot. 14: 263 (1876); Lecidea apostatica (Nyl. ex Cromb.) Hue, Nouvelles archives du Muséum d histoire naturelle, sér. 5, 4: 9 (1914); Blastenia apostatica (Nyl. ex Cromb.) Zahlbr., Cat. Lich. Univ 7: 24 (1930); Huea apostatica (Nyl. ex Cromb.) C. W. Dodge, Beih. Nova Hedwigia 38: 84 (1971). Type: Rodrigues, on rocks, 1874, Balfour (BM !, lectotypus hic designatus; E, H, syntypes, non vid.). MycoBank MBT Syn. nov.: Lecanora apostatica var. obliquans Nyl. ex Cromb., J. Bot. 14: 263 (1876); Lecidea obliquans (Nyl. ex Cromb.) Hue, Nouvelles archives du Muséum d histoire naturelle, sér. 5, 4: 16 (1914); Blastenia obliquans (Nyl. ex Cromb.) Zahlbr., Cat. Lich. Univ. 7: 37 (1930); Huea obliquans (Nyl. ex Cromb.) C. W. Dodge, Beih. Nova Hedwigia 38: 87 (1971). Type: Rodrigues, on rocks, 1874, Balfour (BM !, lectotypus hic designatus; BM !, BM !, BM !, BM !, syntypes; E, H, syntypes, non vid.). MycoBank MBT Description. Thallus white to pale yellowish or greyish, varying from thin and continuous to thick and cracked or areolate, up to 0.3 mm thick. Apothecia abundant, dispersed, sessile with a constricted base, mm diam.; disc slightly concave, brownish to greenish black, becoming dark greenish in damaged areas, without pruina; proper margin greenish black, 70 ( 120) µm thick, often becoming slightly to strongly undulate, some apothecia eventually becoming gyrose; thalline margin absent. Hymenium not inspersed, hyaline, in the upper part bluish green, µm thick; epihymenium not granulose, with a bluish green, K pigment, additionally appearing brownish because of the paraphyses tips; hypothecium hyaline, 50 µm thick; exciple µm, outer layer greenish, K, inner layer hyaline, of rounded cells µm diam. Paraphyses branched in the middle or close to the apex, µm thick, apically brownish, up to 3 µm. Asci claviform, wall apically thickened, 8-spored, µm. Ascospores polarilocular, ellipsoid, µm (Diederich 18400), or (11 ) ( 10.5) µm (lectotype of L. apostatica), or µm (original description), septum 2.5 4( 5) µm wide. Pycnidia immersed, blackish; pycnidial wall absent; ostiolar region bluish green, K ; conidiophores hyaline, irregularly branched, occupying almost the entire pycnidial cavity, septate; conidiogenous cells enteroblastic, integrated into chains, acro-pleurogenous; conidia arising from the apex of a chain and laterally, hyaline, bacilliform, aseptate, µm. Chemistry: thallus K+ yellow, C, KC, PD, UV ; no substance detected by TLC (solvent A). Ecology and distribution. Previously known only from Rodrigues, where the large number of specimens available in different herbaria suggests that it is a relatively common species. We collected it in one Mauritius locality near Chamarel. Notes. Crombie (1876a) published the new species 8. L. apostatica, Nyl. and the new taxon L. obliquans, Nyl. ; all new species in his paper were preceded by a number, except L. obliquans, preceded by. In Crombie (1876b), all new species, including L. apostatica, were followed by sp. n., while L. obliquans was not. Several original herbarium specimens examined are annotated as Lecanora apostatica obliquans Nyl.. This clearly shows that obliquans was intended to be published as a new variety, not a new species. Crombie (1876a) published both taxa based on minor differences. Lecanora apostatica was said to be characterized by Thallus whitish, thin, areolato-rimose, while var. obliquans differs in having the thallus greyish, very thin, continuous. Examination of five original specimens (one of L. apostatica and four of var. obliquans) and our recent material convinced us that they all belong to a single species with a rather variable thallus. A phylogenetic analysis, using nulsu and mtssu sequences from our recent specimen, places Lecanora apostatica in a poorly supported clade comprising also the genera Eilifdahlia, Frankwilsia, Gyalolechia, Huneckia, Jasonhurea and Loekoesia. In the combined nulsu/mtssu tree (not shown here), the species does not group in a convincing way with any of these genera. In the mtssu tree (Fig. 10), our species groups with Loekoesia austrocoreana but without any support, similarly to the other genera from this clade that are also not supported. No nulsu sequences are available yet for L. austrocoreana. Morphologically, Lecanora apostatica is extremely similar to Loekoesia austrocoreana. That species has a grey to greyish white, cracked or areolate thallus, black apothecia mm diam., a plane, brownish black disc, a prominent, bluish black margin, an 80 µm thick, greenish blue, K exciple, a µm high hymenium with a bluish epihymenium, and ascospores µm in K (Kondratyuk et al. 2013). It differs from L. apostatica by a thallus presenting bluish soralia, mm diam., and paraphyses tips up to 4 5 µm.

31 P. Diederich & D. Ertz: First checklist of lichens and lichenicolous fungi from Mauritius 43 We conclude that Lecanora apostatica either belongs to Loekoesia or represents a distinct genus closely related to that genus. Owing to the very low molecular support and the remarkable resemblance of Lecanora apostatica and Loekoesia austrocoreana, we decided to combine L. apostatica in Loekoesia. The species is new for the island of Mauritius. Additional specimens examined. MAURITIUS. Rivière Noire: Chamarel, Ebony Forest, around viewpoint, saxicolous, on exposed rocks, 2016, Diederich LOPADIUM Körb. leucoxanthum (Spreng.) Zahlbr. Brigantiaea leucoxantha Figure 9. Loekoesia apostatica [A: lectotype of Lecanora apostatica; B: lectotype of Lecanora apostatica var. obliquans; C H: Diederich 18518]. A D thalli with apothecia; note the undulate margin of upper left apothecium in B and of most apothecia in D; E section through apothecium, in water; F ascospores, in KOH; G hymenium with paraphyses, asci and ascospores, in KOH; H paraphyses, in KOH. Scales: A D = 500 µm; E = 50 µm; F = 5 µm; G H = 10 µm. Photos: P. Diederich.

32 44 Plant and Fungal Systematics 65(1): 13 75, Austroplaca lucens KC Gondwania cribrosa KC Xanthopeltis rupicola KC Xanthocarpia epigaea KC Pachypeltis invadens KC Parvoplaca tiroliensis KC Xanthomendoza borealis KC Orientophila sp. 21 KC Xanthoria resendei KC Flavoplaca citrina KC Xanthorioideae Squamulea squamosa KC Squamulea cf. squamosa PD Squamulea subsoluta KC Athallia cerinelloides KC Athallia holocarpa KC Rusavskia elegans KC Solitaria chrysophthalma KC Dufourea flammea KC Polycauliona candelaria KC Calogaya arnoldii s. lat. KC Cerothallia luteoalba KC Shackletonia hertelii KC Shackletonia sauronii KC Yoshimuria spodoplaca KJ Josefpoeltia parva KC Teloschistes flavicans KC Villophora isidioclada KC Teloschistopsis eudoxa KC Teloschistopsis bonae-spei KC Sirenophila maccarthyi KC Haloplaca sp. 6 KC Kaernefia kaernefeltii KF Brownliella montisfracti KF Filsoniana australiensis KF Stellarangia elegantissima KC Scutaria andina KC Wetmoreana decipioides KC Catenarina desolata KF Franwilsia kilcundaensis KJ Franwilsia bastowii KJ Franwilsia renatae KJ Eilifdahlia wirthii KJ Eilifdahlia dahlii KJ Eilifdahlia dahlii KJ Gyalolechia arizonica KC Gyalolechia flavovirescens KC Gyalolechia stantonii KC Huneckia pollinii KJ Jasonhuria bogilana KT Loekoesia apostatica PD18518 comb. nov. Loekoesia austrocoreana KT Fauriea chujaensis KX Fauriea orientochinensis KX Marchantiana occidentalis KJ Caloplaca cerina KC Caloplaca chlorina KC Seirophora scorigena KC Seirophora lacunosa KC Variospora aurantia KC Variospora velana KC Leproplaca proteus KT Leproplaca obliterans KC Leproplaca xantholyta KC Caloplaca erythrocarpa KC Caloplaca atroflava KC Pyrenodesmia variabilis KC Pyrenodesmia chalybaea MH Pyrenodesmia alociza MH Usnochroma scoriophila KC Usnochroma carphinea KC Caloplacoideae 25 Rufoplaca scotoplaca KC Olegblumia demissa MH784 Olegblumia demissa KC Bryoplaca sinapisperma KC Bryoplaca tetraspora KC Blastenia ferruginea KC Blastenia crenularia KC Megalospora tuberculosa AY Megaloblastenia marginiflexa JQ Sipmaniella sulphureofusca JQ Letrouitia vulpina KC Brigantiaea sp. 11 KC Figure 10. Phylogeny of Teloschistales based on a data set of mtssu sequences that resulted from a RAxML analysis. Maximum likelihood bootstrap values are shown above or near internal branches. Internal branches considered strongly supported by both the RAxML and Bayesian analyses are represented by thicker lines. The newly sequenced samples from Mauritius are highlighted and their names followed by collecting numbers of authors, which act as specimen and sequence identifiers. Their respective subfamilies are indicated.

33 P. Diederich & D. Ertz: First checklist of lichens and lichenicolous fungi from Mauritius 45 MEDUSULA Tode tricosa (Ach.) Mont. Sarcographa tricosa MEGALOSPORA Meyen atrorubicans (Nyl.) A. Zahlbr. subsp. atrorubicans Reported from Mauritius, 1867 (BM) by Sipman (1983: 96, 230). coccodes (Bél.) Sipman subsp. coccodes = Lecanora vigilans Taylor, J. Bot., London 6: 159 (1847). Type: Mauritius, on bark (G , isotype; FH-Taylor, sheet 644, isotype) (Sipman 1983: 132; Taylor 1847: 159). Also reported from Mauritius, Ayres (BM) by Sipman (1983: 230). sulphurata Meyen s.str. = Lecidea megacarpa Nyl., Ann. Sci. Nat., Bot., sér. 4, 11: 260 (1859). Type: Ad cortices in Insula Mauritii, ex herb. cel. Fée (H, isotype?) (Sipman 1983: 126). Rivière Noire: Trail from Plaine Champagne towards Piton de la Petite Rivière Noire, on bark, 2016, Diederich Also reported from Mauritius by Daruty (1873), anon. 7 (H- NYL), M. Bogn Hub (BM), and Mt Pouce (G) by Sipman (1983: 126), and Pamplemousses Botanical Garden, 1990, Hawksworth (K-IMI) by David & Hawksworth (1995) and Crittenden et al. (1995). tuberculosa (Fée) Sipman Lecidea tuberculosa Fée Plaines Wilhems: Le Pétrin, heathland NW of Pétrin Information Centre, on bark, 2019, Diederich 18816, & Ertz Savanne: Along trail to Mt Cocotte, on bark, 2019, Ertz Also reported Sur l écorce des arbres, à l île Maurice (Bélanger 1834). Sipman (1983: 161) suggested on a distribution map (fig. 40) that this species occurs in Mauritius and Reunion; however, on p. 230, a specimen from Reunion and a second specimen from Mascarene Islands from herb. Bory de Saint-Vincent (PC-Thuret), but without indication of locality, are given. Crittenden et al. (1995) further reported the species, as M. cf. tuberculosa, from Savanne, Plaines Champagne, at viewpoint of Black River Gorge, 1990, Hawksworth (K-IMI). MELANOTREMA A. Frisch platystomum (Mont.) A. Frisch Plaines Wilhems: Le Pétrin, between Pétrin Information Centre and first viewpoint along trail to the west, on bark, 2016, Diederich (TLC: no substance detected, solvent A). MELASPILEA Nyl. +cf. lekae Brackel & Kalb Pamplemousses: Sir Seewoosagur Ramgoolam Botanical Garden, on bark of Ptychosperma macarthurii, on Phaeographis intricans, 2016, Ertz Melaspilea lekae was described from Thailand as a lichenicolous fungus on Sarcographa labyrinthica (Kalb et al. 2012). Our specimen is on a new host genus, and the ascospores are slightly smaller. Further studies are needed. MYCOMICROTHELIA Keissl. leuckertii D. Hawksw. & J. C. David Bogoriella leuckertii MYCOPORUM G. Mey. eschweileri (Müll.Arg.) R. C. Harris Tomasellia eschweileri (Müll. Arg.) R. C. Harris Moka: Réduit, State House Park, on bark of Phyllanthus emblica, 2019, Diederich Plaines Wilhems: Curepipe Botanic Gardens, on bark of Pinus, 2019, Diederich 19107; ibid., on bark, Diederich Also reported from Flacq, Sandy Bay Hotel, on Cocos nucifera, 1990, Hawksworth (K-IMI) by David & Hawksworth (1995) and Crittenden et al. (1995). MYRIOTREMA Fée microporum (Mont.) Hale = Thelotrema crassulum Nyl. [fide Frisch (2006: 177)]. Plaines Wilhems: Le Pétrin, heathland NW of Pétrin Information Centre, on bark, 2019, Ertz T. crassulum was described by Nylander (1859: 258) in the chapter Lichenes Insulae Borboniae, i.e. from Reunion. Later, this was inadvertently cited as Mauritius (Dodge 1964: 93) or Mauritius [ Bourbon ] (Frisch 2006: 177). The former report from Mauritius is therefore erroneous. Our specimen has a mainly white thallus similar to the type specimen of Thelotrema crassulum described from Reunion. olivaceum Fée [ Thelotrema olivaceum (Fée) Mont.]. Reported from Mauritius by Daruty (1873). NIGROVOTHELIUM Lücking, M. P. Nelsen & Aptroot tropicum (Ach.) Lücking, M. P. Nelsen & Aptroot [ Verrucaria tropica Ach.]. Sur l écorce des arbres, dans les forêts de la péninsule indienne et dans les bois de la Montagne-Noire à l île Maurice (Bélanger 1834) (PC ). NORMANDINA Nyl. pulchella (Borrer) Nyl. Rivière Noire: Trail from Plaine Champagne towards Piton de la Petite Rivière Noire, on bark, 2016, Diederich Savanne: Near Grand Bassin, on bark, 2019, obs. Ertz & Diederich (no specimen). Previously reported from Macchabee Forest, 1990, Hawksworth (K-IMI) by David & Hawksworth (1995). NYUNGWEA Sérus., Eb. Fischer & Killmann Nyungwea pyneei Ertz & Diederich, sp. nov. (Figs 4, 11) MycoBank MB Diagnosis: A species of Nyungwea producing goniocysts on slightly convex cushions, without forming distinct stipes. Type: Mauritius, Pamplemousses district, Pamplemousses, Sir Seewoosagur Ramgoolam Botanical Garden, S, E, alt. 80 m, on bark of trees, 28 July 2016, Diederich (MAU holotype, BR, LG, herb. Diederich isotypes). Description. Thallus corticolous, crustose, very thin and partly endophloeodal and intermingled with dead cells of bark, up to 40 µm thick, continuous, white, I+ pale orange;

34 46 Plant and Fungal Systematics 65(1): 13 75, 2020 hyphae hyaline, smooth, branched, without crystals, 1 2 µm diam., I+ pale orange. Prothallus not seen, but the presence of a dark brown to black borderline ~ mm wide formed in contact with other lichens. Photobiont trentepohlioid; cells subspherical to ± oblong-elongated, µm, sometimes densely filling a dead cell of the bark. Goniocyst-producing thallus cushions numerous, white to pale cream, becoming greenish just below the layer of goniocysts when abraded, rounded, without or with a slightly constricted base, µm diam, sometimes fused forming irregular patches of up to 1( 2) mm diam, slightly raised above the level of the thallus, up to 160 µm high when single and up to 280 µm high when forming larger patches, containing numerous colourless crystals 1 7 µm diam. dissolving in K. Hyphae forming cushions hyaline, richly branched, a few anastomosed, µm, I+ pale orange. Goniocysts numerous on upper surface of thallus cushions, dark brown when mature, formed of a single trentepohlioid algal cell (or rarely a couple of them) that is tightly embedded in a branched network of short dark brown hyphae, 8 10 µm diam; these hyphae stay tightly on the algal cell without forming hairs and do not form any structure that could be Figure 11. Nyungwea pyneei [A, C F: holotype; B: Ertz 21450]. A D thallus with goniocyst-producing cushions; E F goniocysts in water. Scales: A C = 1 mm; D = 250 µm; E F = 10 µm. Photos: D. Ertz.

35 P. Diederich & D. Ertz: First checklist of lichens and lichenicolous fungi from Mauritius 47 described as paraplectenchymatous or a cortex of isodiametric cells. Goniocysts easily detached from their thallus cushions and act as diaspores. Ascomata and conidiomata absent. Chemistry: thallus K, C, P, UV ; goniocyst-producing thallus cushions K, C+ red, P, UV ; lecanoric acid detected by TLC (solvents B, EA). Ecology and distribution. The species is only known from the Sir Seewoosagur Ramgoolam Botanical Garden in Mauritius, where it grows on the bark of trees, including Swietenia mahagoni. Notes. The generic placement is confirmed by our phylogeny, where the new species groups with the generic type (Fig. 4). The new species is unique in having slightly convex goniocyst-producing thallus cushions. Nyungwea pallida Sérus., Eb. Fischer & Killmann described from the mountains of East Africa differs by goniocysts producing on distinct stipes up to 1 mm long and by paler goniocysts (Sérusiaux et al. 2006). Etymology. The new species is dedicated to Mauritian botanist Kersley Pynee, formerly working in The Mauritius Herbarium, now Technical Officer at the Ministry of Agro Industry and Food Security in Mauritius, to thank him for having guided us during several collecting trips in Additional specimen examined. MAURITIUS. Same locality as the type, on bark of Swietenia mahagoni, 2016, Ertz OCELLULARIA G. Mey. bahiana (Ach.) Frisch [ Thelotrema bahianum (Ach.) Ach.]. Reported from Mauritius by Daruty (1873). bonplandii (Fée) Müll. Arg. [ Thelotrema bonplandii Fée]. Sur l écorce des arbres de la montagne du Pouce, à l île Maurice (PC ) (Bélanger 1834). cavata (Ach.) Müll. Arg. [ Thelotrema cavatum Ach.]. Reported from Mauritius by Daruty (1873). mauritiana Hale Mycotaxon 3: 175 (1975). Type: Mauritius: Pouce, Ayres (BM, holotype; US, isotype) (Frisch & Kalb 2006: ). Port Louis and Moka: Along trail from Moka to Le Pouce, on bark, 2019, Ertz A pantropical species (Frisch & Kalb 2006). Our specimen comes from the type locality (Le Pouce) and has slightly more septate ascospores, (3 )5 7-septate, than in the description by Frisch & Kalb (2006; 3 5( 6)-septate). petrinensis J. C. David in David & Hawksworth, Biblioth. Lichenol. 57: 99 (1995). Type: Plaines Wilhems, Vacoas, Le Pétrin Nature Reserve, heathland, ~640 m, in cortice Sideroxyli puberuli, 11 June 1990, Hawksworth (K-IMI , holotype) (David & Hawksworth 1995; Crittenden et al. 1995). Plaines Wilhems: Le Pétrin, heathland NW of Pétrin Information Centre, on bark, 2019, Ertz 23338; Curepipe, Curepipe Botanical Gardens, on bark, 2019, Ertz 24230; Curepipe, Trou aux Cerfs, along road surrounding the crater, on bark, 2019, Ertz Rivière Noire: Trail from Plaine Champagne towards Piton de la Petite Rivière Noire, on bark, 2019, Ertz A pantropical species, also known from Australia (Lücking & Pérez-Ortega 2015) and Venezuela (Kraichak et al. 2014). OCHROLECHIA A. Massal. africana Vain. = Lecanora parella var. phloeoleuca Nyl., in Crombie, Journ. Linn. Soc., Bot. 15: 440 (1876); Ochrolechia parella f. phloeoleuca (Nyl.) Zahlbr., Cat. Lich. Univ. 5: 690 (192). Type: Rodrigues, on bark of trees (twigs), 1874, Balfour 2330 (H-NYL 3635, type?, verified by M. Kukwa 2006; H-NYL 23919). Rivière Noire: Trail from Plaine Champagne towards Piton de la Petite Rivière Noire, on bark, 2016, Diederich 18675; Brise Fer Forest, on bark, 2019, Diederich (MAU). Specimen presents numerous young, immature apothecia, while in specimen all apothecia are old. Both are, however, well characterized by the white thallus with a rugose surface, a cortex not giving any positive reactions, and a medulla and a hymenium that are C+ red (Brodo 1991). The species is new for the island of Mauritius. pallescens (L.) A. Massal. [ Lecanora parella var. pallescens (L.) Ach.]. Reported from Mauritius by Daruty (1873). OPEGRAPHA Ach. angulosa Müll. Arg. = Opegrapha semiatra atra Pers. var. abbreviata Flörke, see Arthonia atra bonplandii Fée Zwackhia bonplandii dendritica Ach. Phaeographis dendritica difficilior Nyl. ex Cromb. Journ. of Bot. 14: 264 (1876). Type: Rodrigues, on decaying (decorticated) stumps of trees, 1874, Balfour 2251 (H-NYL 6802, lectotype, designated by Ertz 2009; BM, N-Nyl 6208, isolectotypes) (Crombie 1876a, b; Ertz 2009). Moka: Réduit, close to Mauritius Herbarium building, on bark of Mangifera, 2019, Ertz Pamplemousses: Jardin Botanique, on bark of Mangifera, 2016, Ertz 21442, 21504; ibid., on bark, Ertz 21487, 21493; ibid., on bark of Terminalia, Ertz The species is also known from Kenya and West Africa (Ertz 2009), and is here reported as new for the island of Mauritius. duplicata (Ach.) Bél. Graphis duplicata +foreaui (Moreau) Hafellner & R. Sant. = Opegrapha trassii S. Y. Kondr. & Coppins Rivière Noire: Trail from Plaine Champagne towards Piton de la Petite Rivière Noire, on bark, on Heterodermia, 2019, Ertz A lichenicolous fungus, previously reported from Mauritius, on Heterodermia obscurata, Ayres (E) by Coppins & Kondratyuk (1998). laubertiana (Fée) Bél. Allographa laubertiana poitaei (Fée) Bél. Diorygma poitaei rugulosa Fée Graphis rugulosa semiatra Müll. Arg. = Opegrapha angulosa Müll. Arg., Journ. Linn. Soc., Bot. 30: 457 (1895). Type: Mauritius, Pouce, 1894, Ayres (G , holotype) (Ertz 2009: 99). Rivière Noire: Chamarel, Ebony Forest, around viewpoint, on bark, 2019, Ertz

36 48 Plant and Fungal Systematics 65(1): 13 75, 2020 sordida (Fée) Mont. & Bosch Phaeographis sordida trassii S. Y. Kondr. & Coppins = Opegrapha foreaui OXYSTOMA Eschw. friesianum Bél. [as Friesana ], Voyage aux Indes-orientales, pendant les années : 132 (1834). Type: Sur l écorce des arbres, dans le quartier des Pampelmousses, à l île Maurice, Bélanger (PC , G ). According to the type specimen (G , photograph on JSTOR) the species might belong to the genus Celothelium. PANNARIA Delise ex Bory cinerascens (Nyl.) P. M. Jørg. Biblioth. Lichenol. 88: 241 (2004); Pannaria rubiginosa f. cinerascens Nyl., in Crombie, Bot. J. Linn. Soc. 15: 436 (1876). Type: Rodrigues, on rocks, 1874, Balfour 2321 (BM, lectotype, selected by Jørgensen 2004). Also reported from the forested mountainside between Yemen and Mt Brise Fer, 1991, Krog & Timdal (O) by Jørgensen (2004: 242). luridula Nyl. ex Cromb. = Lepidocollema marianum macrocarpa Müll. Arg. Hedwigia 31: 277 (1892). Type: In ins. Mauritii cum Psoromate sphinctrino, corticola, Ayres (G , K). Further unpublished specimens from Le Pouce, Mt Cocotte and Piton de la Petite Rivière Noire, collected by Krog & Timdal in 1991, are kept in O. multifida P. M. Jørg. Reported from Piton de la Petite Rivière Noire, Macchabee Forest (0.5 1 km ESE of Macchabee Kiosk) and along the road between Mt Cocotte and Bassin Blanc, 1991, Krog & Timdal (O) (Jørgensen 2004: 241; Lücking & Timdal 2016: 194; all det. Jørgensen 2002). Further unpublished specimens from Le Pouce and Mt Cocotte, collected by Krog & Timdal in 1991 and identified by Jørgensen in 2002, are kept in O. pannosa Nyl. Parmeliella pannosa pruinosa P. M. Jørg. & Timdal Biblioth. Lichenol. 88: 242 (2004). Type: Savanne, Mt Cocotte, along path towards the peak, 11 Nov. 1991, Krog & Timdal MAU 32/56 (O L-21609, holotype). Also reported from Piton de la Petite Rivière Noire, Le Pouce and Mt Cocotte, 1991, Krog & Timdal (O) by Jørgensen (2004). ramosii Vain. Reported from the road between Mt Cocotte and Bassin Blanc, 1991, Krog & Timdal (O) by Lücking & Timdal (2016: 194). Further unpublished specimens from Piton de la Petite Rivière Noire, Macchabee Forest, Mt des Créoles, Le Pouce, Pétrin and Mt Cocotte, collected by Krog & Timdal in 1991 and some identified by Jørgensen in 2002, are kept in O. rubiginosa (Thunb.) Delise. Reported from Mauritius by Lindau (1908). rubiginosa f. cinerascens Nyl. Pannaria cinerascens rubiginosa var. dispartita Nyl., see Lepidocollema brisbanense santessonii Swinscow & Krog Reported from the viewpoint WNW of Mt Cocotte, 1991, Krog & Timdal (O) by Lücking & Timdal (2016: 194). Further unpublished specimens from Pétrin and Mt Cocotte, collected by Krog & Timdal in 1991, are kept in O. sphinctrina (Mont.) Hue [ Psoroma sphinctrinum (Mont.) Nyl.]. Reported from the road between Mt Cocotte and Bassin Blanc, 1991, Krog & Timdal (O) by Lücking & Timdal (2016: 194); also from Mauritius by Daruty (1873) and Nylander (1859: 256). Reports of this species should be revised, as most Mauritius herbarium specimens named P. sphinctrina in the past proved to represent species of Gibbosporina (Elvebakk et al. 2016). PARACARPIDIUM Müll. Arg. johnstoni Müll. Arg. Endocarpon johnstonii PARMELIA Ach. afromontana Parnell, J. Trop. Ecol. 5: 374 (1989), nom. nud. (description missing). Original material: Ile aux Aigrettes, on Maytenus pyria, Parnell et al. (1989), BM, det. James. appendiculata Fée Parmotrema appendiculatum atrichoides Nyl. Rodrigues, on rocks, 1874, Balfour 2227 (Crombie 1876b). caperata (L.) Ach. Flavoparmelia caperata caraccensis f. isidiosa Müll. Arg. = Hypotrachyna microblasta conspersa (Ehrh. ex Ach.) Ach. Xanthoparmelia conspersa crenulata Hook. f. Lobariella crenulata cristifera Tayl. Parmotrema cristiferum darutyi Wedd., in Daruty, Trans. Roy. Soc. Arts Mauritius, n.s. 7: 165 (1873), nom. nud. (description missing). decorata (Hue) Dodge = Parmotrema reticulatum glomulifera (Lightf.) Ach. = Ricasolia amplissima hildenbrandtii Kremp. Reported from Rodrigues, 1874, Balfour (K) by Dodge (1959: 150). imerinensis Dodge = Parmotrema cristiferum latissima Fée Parmotrema latissimum limbata Laurer Relicina limbata mauritiana Gyeln. = Hypotrachyna microblasta meiosperma (Hue) Dodge. Reported from Mauritius, on the Bruce, on trees, Ayres (K), and Pouce, Ayres (K, several specimens) by Dodge (1959: 140), and from Rodrigues, 1874, Balfour 2249 (K) by Dodge (1959: 140). microblasta Vain. Hypotrachyna microblasta olivetorum Nyl. Cetrelia olivetorum ornata (Hue) Dodge = Parmotrema reticulatum pannosa (Sw.) Sw. Parmeliella pannosa perforata (Wulfen) Ach. Parmotrema perforatum perlata (Huds.) Ach. Parmotrema perlatum perlata var. ciliata (DC.) Duby. Reported from Mauritius by Daruty (1873). Almost surely belongs to Parmotrema.

37 P. Diederich & D. Ertz: First checklist of lichens and lichenicolous fungi from Mauritius 49 pulverulenta (Schreb.) Ach. = Physconia distorta punicea (Sw.) Ach. Haematomma puniceum quercizans var. denudata Laurer = Ricasolia sublaevis saccatiloba Taylor Parmotrema saccatilobum sieberi Dodge = Parmotrema dilatatum sorediifera (Fée) Bél. Lecanora sorediifera subconspersa Nyl. Xanthoparmelia subconspersa subfuscescens Nyl. Xanthoparmelia subfuscescens subhypoclysta Dodge = Xanthoparmelia subramigera viridula Wedd., in Daruty, Trans. Roy. Soc. Arts Mauritius, n.s. 7: 165 (1873), nom. nud. (description missing). wightii Dodge = Xanthoparmelia phaeophana zeyheri Dodge, see under Xanthoparmelia PARMELIELLA Müll. Arg. endoferruginea Aptroot Reported from the road between Mt Cocotte and Bassin Blanc, 1991, Krog & Timdal (O) by Lücking & Timdal (2016: 194). mariana (Fr.) P. M. Jørg. & D. J. Galloway Lepidocollema marianum pannosa (Sw.) Müll. Arg. [ Pannaria pannosa Nyl.]. Reported from Mauritius by Daruty (1873) and Lindau (1908), and Sur les arbres, dans les lieux humides des forêts, aux îles Maurice et de Bourbon by Bélanger (1834). papillata P. M. Jørg. Lepidocollema papillatum stylophora (Vainio) P. M. Jørg. Lepidocollema stylophorum PARMOTREMA A. Massal. acrotrychum (Kurok.) Streimann Plaines Wilhems: Le Pétrin, between Pétrin Information Centre and first viewpoint along trail to the west, on bark, 2016, Diederich (det. Masson; TLC: atranorin, protolichesterinic, fumarprotocetraric, succinprotocetraric). appendiculatum (Fée) Hale [ Parmelia appendiculata Fée]. Reported from Mauritius (FH: herb. Tuckerman sub P. perlata var. ciliata) by Dodge (1959: 171). crinitum (Ach.) Choisy Reported from Mauritius by Crittenden et al. (1995, as Parmotrema cf. crinitum). Other unpublished specimens from Le Pouce and Curepipe (Trou aux Cerfs), collected in 1991 by Krog & Timdal, are kept in O. A further specimen named Parmelia crinita and collected in 1802 by Bory de Saint-Vincent sur les grands arbres at Le Pouce is kept in PC (PC ). cristiferum (Taylor) Hale Parmelia cristifera Taylor; = Parmelia imerinensis Dodge Reported from Mauritius, Wright (BM, FH ) by Hale (1965: 243) and Krog & Swinscow (1981: 174), Robillard (M, US) by Hale (1965: 243), Réduit, Orian 7 (K) by Dodge (1959: ), and from Ile aux Aigrettes (BM, det. James) by Parnell et al. (1989). dilatatum (Vain.) Hale Parmelia dilatata Vain. = Parmelia sieberi C. W. Dodge, Ann. Missouri Bot. Gard. 46: 148 (1959). Type: Mauritius, corticole, Sieber, Crypt. Exot. 44 (FH ) (Dodge 1959: 117, ; Hale 1965: 245). Plaines Wilhems: Curepipe, Curepipe Botanic Gardens, on bark, 2016, Diederich (det. Masson; TLC: atranorin, usnic, protocetraric, echinocarpic). Previously also reported from Mauritius, Robillard (FH, sub Parmelia cristifera), Wight (FH-Tayl, sub Parmelia cristifera) and Pouce, Ayres (K) by Dodge (1959: 149). latissimum (Fée) Hale [ Parmelia latissima Fée]. Reported from Rodrigues, on trees and rocks, 1874, Balfour 2249, 2205 by Crombie (1876b). perforatum (Wulfen) A. Massal. [ Parmelia perforata (Wulfen) Ach.]. Reported from Mauritius by Daruty (1873). perlatum (Huds.) M. Choisy [ Parmelia perlata (Huds.) Ach.]. Reported from Mauritius by Laurer (1827). reticulatum (Taylor) M. Choisy Rimelia reticulata (Taylor) Hale & Fletcher; = Parmelia decorata (Hue) Dodge; = Parmelia ornata (Hue) Dodge Rivière Noire: Chamarel, Ebony Forest, around viewpoint, on bark, 2016, Diederich [det. Masson; TLC: atranorin, salazinic (major), consalazinic (minor)]. Previously also reported from Mauritius by Crittenden et al. (1995), Moka, below Mt Ory, on shaded volcanic rocks by a track, 1990, Hawksworth (K-IMI) by David & Hawksworth (1995), Pamplemousses Botanical Garden, on bark, 1990, Hawksworth (K-IMI) by David & Hawksworth (1995), and Grand Port, Mt des Créoles, 1991, Krog & Timdal (O) by Lücking & Timdal (2016: 198). Also, as P. ornata, from Mauritius, Wight (FH-Tayl, glued to sheet with P. cristifera Tayl.), and Bojer (K: herb Hooker) (Dodge 1959: 98), and as P. decorata from Robillard (FH, sub P. perlata var. olivetorum Nyl., det. Müll. Arg.) by Dodge (1959: 96). Further unpublished specimens from Mt Corps de Garde, Macchabee Forest, Riche en Eau, Ile aux Aigrettes, Réduit, Le Pouce and Henrietta, collected by Krog & Timdal in 1991, are kept in O. saccatilobum (Taylor) Hale = Parmotrema tinctorum subcorallinum (Hale) Hale Parmelia subcorallina Hale Reported from Mauritius, Robillard (G) by Hale (1962, 1965: 310). A further unpublished specimen from Pétrin heath, collected by Krog & Timdal in 1991, is kept in O. subisidiosum (Müll. Arg.) Hale Rivière Noire: Trail from Plaine Champagne towards Piton de la Petite Rivière Noire, on bark, 2016, Diederich [det. Masson; TLC: atranorin, salazinic (major), consalazinic (minor)]. A further specimen from Le Pouce, collected by Krog & Timdal in 1991, is kept in O. tinctorum (Delise ex Nyl.) Hale agg. = Parmelia saccatiloba Taylor; Parmotrema saccatilobum (Taylor) Hale Pamplemousses: Jardin Botanique, on bark, 2016, Diederich 18233, 18266, Ertz Rivière Noire: Chamarel, Ebony Forest, around viewpoint, on bark, 2016, Diederich

38 50 Plant and Fungal Systematics 65(1): 13 75, ; trail from Plaine Champagne towards Piton de la Petite Rivière Noire, on bark, 2016, Diederich Plaines Wilhems: Curepipe, Curepipe Botanic Gardens, on bark, 2016, Diederich 18299, (all det. Masson, except Ertz 21476; TLC (all Diederich, except 18595): atranorin, lecanoric). Also reported from Mauritius by Hale (1965: 262), from Grand Port, Mt des Créoles, 1991, Krog & Timdal (O) and Grand Port, Bambou Mountains, 1991, Krog & Timdal (O) by Lücking & Timdal (2016: 192, 198), from Pamplemousses Botanical Garden, 1990, Hawksworth (K-IMI) by David & Hawksworth (1995), and from Mauritius by Crittenden et al. (1995, as Parmotrema cf. tinctorum). Further unpublished specimens from Piton de la Petite Rivière Noire, Morne Brabant, Macchabee Forest, between Yemen and Mt Brise Fer, Mt Corps de Garde, Baie du Cap, Flacq, Riche en Eau, Réduit, Le Pouce, Pamplemousses Botanical Garden, Curepipe (Trou aux Cerfs), Henrietta, Tamarin Falls and Mt Cocotte, collected by Krog & Timdal in 1991, are kept in O. zollingeri (Hepp) Hale Parmelia zollingeri Hepp Reported from Mauritius, McGregor s.n. (BM) by Hale (1965: 268). PELTIDEA Ach. floerkeana Laurer = Coccocarpia erythroxyli PELTULA Nyl. rodriguesii (Cromb.) Büdel Lichenologist 21: 293 (1989); Heppia rodriguesii Cromb., J. Bot. 14: 263 (1876). Type: Rodrigues, on rocks, 1874, Balfour 2302 (BM, lectotype, selected by Büdel 1989); Balfour 2233 (BM, isolectotype) (Büdel 1987, 1989; Crombie 1876a, b). The species is widespread and further known from Italy, Cape Verde Islands, South Africa, Zimbabwe and Australia (Büdel 1989). PERTUSARIA DC. cicatricosa Müll. Arg. = Pertusaria subtruncata Müll. Arg., Flora 67: 397 (1884). Type: Mauritius, 1876, Robillard (G , holotype) (Archer 1997: 51). communis DC. = Pertusaria pertusa communis var. minor Müll. Arg. Pertusaria pertusa var. minor hymenelioides J. C. David in David & Hawksworth, Biblioth. Lichenol. 57: 101 (1995). Type: Moka, sub monte Ory, in petris vulcanicis secundum viam, 12 June 1990, Hawksworth (K-IMI , holotype) (David & Hawksworth 1995; Crittenden et al. 1995). impallescens Nyl. ex Cromb. J. Bot. 14: 264 (1876). Type: Rodrigues, on rocks, 1874, Balfour 2214 (Crombie 1876a, b). This poorly known species is accepted by Archer (1997: 164) and keyed out by Archer & Elix (2018). leioplaca DC. Reported from Mauritius by Daruty (1873). margaritifera Zahlbr. Reported from Mauritius by Daruty (1873). muricata J. C. David in David & Hawksworth, Biblioth. Lichenol. 57: 102 (1995). Type: Plaines Wilhems, Vacoas, Le Pétrin Nature Reserve, in cortice, 11 June 1990, Hawksworth (K-IMI , holotype) (Archer 1997: 111; David & Hawksworth 1995; Crittenden et al. 1995). Plaines Wilhems: Le Pétrin, heathland NW of Pétrin Information Centre, on bark, 2019, Ertz (TLC: constictic, stictic and trace of norstictic, solvent A). pertusa (L.) Tuck. [= Pertusaria communis DC. (illeg., nom. superfl.)]. Reported from Mauritius by Daruty (1873), and from Flacq, near Mare La Chaux village, on bark of Delonix regia, 1990, Hawksworth (K-IMI ) by Crittenden et al. (1995). pertusa var. minor (Müll. Arg.) Zahlbr., Cat. Lich. Univ. 5: 201 (1928); Pertusaria communis var. minor Müll. Arg., Lichenol. Beitr. VI, Flora 60: 478 (1877). Type: Mauritius, Robillard. Also reported from Mauritius by Dodge (1964: 253). pertusella Müll. Arg. Flora 67: 283 (1884). Type: Mauritius, 1876, Robillard (G , holotype) (Archer 1997: 124). A rare Paleotropical species. subtruncata Müll. Arg. = Pertusaria cicatricosa trypetheliiformis Nyl. Reported from Mauritius by Daruty (1873). velata (Turn.) Nyl. Varicellaria velata PHAEOGRAPHINA Müll. Arg. heterospora (Nyl.) Zahlbr. Sarcographina heterospora PHAEOGRAPHIS Müll. Arg. aequabilis (Wedd. ex Nyl.) Zahlbr., Cat. Lich. Univ. 2: 364 (1923); Graphis aequabilis Wedd. ex Nyl., Bull. Soc. Linn. Normandie, sér. 2, 7: 175 (1874 [ 1873 ]); G. aequabilis Wedd., in Daruty, Trans. Roy. Soc. Arts Mauritius, n.s. 7: 164 (1873), nom. nud. Type: Mauritius, corticolous (H ). dendritica (Ach.) Müll. Arg. [ Opegrapha dendritica Ach.]. Sur l écorce des arbres, à l île Maurice (Bélanger 1834). intricans (Nyl.) Staiger Pamplemousses: Jardin Botanique, on bark of Ptychosperma macarthurii, 2016, Ertz (sub. Melaspilea cf. lekae) medusuliza Müll. Arg., J. Linn. Soc., Bot. 30: 461 (1895). Type: Corticola, in ins. Mauritii, Balfour (G ). Although the annotation of the specimen and the original publication say that the specimen was collected in Mauritius, it almost surely originates from Rodrigues, where Balfour made extensive collections in scalpturata (Ach.) Staiger [ Graphis scalpturata Ach.]. Reported from Rodrigues, on branches of trees, 1874, Balfour 2365 (Crombie 1876b). sordida (Fée) Müll. Arg. [ Opegrapha sordida (Fée) Mont. & Bosch]. Sur l écorce des arbres, à l île Maurice (Bélanger 1834).

39 P. Diederich & D. Ertz: First checklist of lichens and lichenicolous fungi from Mauritius 51 PHAEOPHYSCIA Moberg hispidula (Ach.) Essl. [= Physcia setosa (Ach.) Nyl.]. Reported from Mauritius, auf Rinde by Lindau (1908). PHYLLOCHARIS Fée elegans Fée = Strigula smaragdula PHYLLOPELTULA Kalb corticola (Büdel & R. Sant.) Kalb Pamplemousses: Jardin Botanique, on bark, 2016, Diederich 18583, Ertz Rivière Noire: La Preneuse (between Tamarin and Grande Rivière Noire), cemetery, on bark at the base of a tree, 2016, Diederich PHYLLOPSORA Müll. Arg., nom. cons. prop. africana Timdal & Krog Reported from Piton de la Petite Rivière Noire, 1991, by Timdal & Krog (2001). albicans Müll. Arg. The report of this species from Mauritius by Timdal & Krog (2001) refers to P. porphyromelaena. borbonica Timdal & Krog Rivière Noire: Trail from Plaine Champagne towards Piton de la Petite Rivière Noire, on bark, 2019, Ertz Also reported from Macchabee Forest (0.5 1 km ESE of Macchabee Kiosk), 1991, by Timdal & Krog (2001). Kistenich et al. (2018) showed that this species belongs to Sporacestra A. Massal, but no new combination has been published yet. breviuscula (Nyl.) Müll. Arg. Reported from Macchabee Forest (along path to Mt Brise Fer) and Bambou Mountains (0.5 1 km NNE of Piton Rouge), 1991, by Timdal & Krog (2001). buettneri (Müll. Arg.) Zahlbr. Rivière Noire: Trail from Plaine Champagne towards Piton de la Petite Rivière Noire, on bark, 2019, Ertz (TLC: pannarin and zeorin, solvent A). Also reported from Piton de la Petite Rivière Noire, Macchabee Forest (along path to Mt Brise Fer) and Macchabee Forest (0.5 1 km ESE of Macchabee Kiosk), 1991, by Timdal & Krog (2001), and from the road between Mt Cocotte and Bassin Blanc, 1991, by Lücking & Timdal (2016: 194). castaneocincta (Hue) Kistenich & Timdal Rivière Noire: East of Black River, from Visitor s Centre to Pilgrims Trail, on bark, 2016, Diederich (det. Timdal). chlorophaea (Müll. Arg.) Müll. Arg. Rivière Noire: Trail from Plaine Champagne towards Piton de la Petite Rivière Noire, on bark, 2016, Diederich (det. Timdal); ibid., 2019, Ertz (TLC: furfuracein, solvent A), (TLC: furfuracein, solvent A). Also reported from Piton de la Petite Rivière Noire, Le Pouce and Mt Cocotte, 1991, by Timdal & Krog (2001). compacta (Nyl.) Gotth. =? Phyllopsora mauritiana confusa Swinscow & Krog Port Louis and Moka: Along trail from Moka to Le Pouce, on rock, 2019, Ertz 24 (TLC: no substance detected, solvent A). Rivière Noire: Chamarel, Ebony Forest, along trail W of viewpoint, on rock, 2019, Ertz (TLC: no substance detected, solvent A). Also reported from Piton de la Petite Rivière Noire and Macchabee Forest (0.5 1 km ESE of Macchabee Kiosk), 1991, by Timdal & Krog (2001), and from the road between Mt Cocotte and Bassin Blanc, 1991, by Lücking & Timdal (2016: 194). dolichospora Timdal & Krog Mycotaxon 77: 76 (2001). Type: Mauritius, Plaine Wilhems, Macchabee Forest, km ESE of Macchabee kiosk, 1991, Krog & Timdal MAU65/22 (O L22197, holotype; CANB, isotype [Elix 2008]]). Rivière Noire: Trail from Plaine Champagne towards Piton de la Petite Rivière Noire, on bark, 2019, Ertz 23918, (TLC of both specimens: furfuracein and two unknown of higher Rf). Also reported from Piton de la Petite Rivière Noire, 1991, by Timdal & Krog (2001). gossypina (Sw.) Kistenich, Timdal, Bendiksby & S. Ekman [ Crocynia gossypina (Sw.) A. Massal.]. Reported from Mauritius by Hue (1892: 182). mauritiana (Taylor) Swinscow & Krog Lichenologist 13: 242 (1981); Lecidea mauritiana Taylor, London J. Bot. 6: 151 (1847). Type: Mauritius, on bark (FH, lectotype, designated by Swinscow & Krog 1981; G ). =? Lecidea compacta Nyl., Ann. Sci. Nat., Bot., sér. 4, 11: 259 (1859); Phyllopsora compacta (Nyl.) Gotth. Schneid., Biblioth. Lichenol. 13: 175 (1979). Type: Mauritius (H-NYL 20654) (Swinscow & Krog 1981). Probably a synonym of Phyllopsora mauritiana, fide Swinscow & Krog (1981: 240). Rivière Noire: Brise Fer Forest, on bark, 2019, Ertz 24291, Also reported from Piton de la Petite Rivière Noire and Macchabee Forest (along path to Mt Brise Fer), 1991, by Timdal & Krog (2001), Kistenich et al. (2018: 903) and Kistenich et al. (2019a). mediocris Swinscow & Krog Rivière Noire: Trail from Plaine Champagne towards Piton de la Petite Rivière Noire, on bark, 2016, Diederich 18396, 18571; Chamarel, Ebony Forest, around viewpoint, on bark, 2016, Diederich 18534, (Kistenich et al. 2019b). Also reported from Macchabee Forest (0.5 1 km ESE of Macchabee Kiosk) and along the Bois Chéri Grand Bassin road, at the bridge over Rivière des Anguilles, 1991, by Timdal & Krog (2001). Crocynia molliuscula (Nyl.) Nyl. Byssocaulon molliusculum Nyl.]. Reported from Mauritius, ad saxa, herb. Fée by Nylander (1859: 259), and from the road between Mt Cocotte and Bassin Blanc, 1991, by Lücking & Timdal (2016: 194) and Kistenich et al. (2019a). Further unpublished specimens from Piton de la Petite Rivière Noire and Macchabee Forest, collected by Krog & Timdal in 1991, are kept in O.

40 52 Plant and Fungal Systematics 65(1): 13 75, 2020 The generic type Crocynia gossypina was recently shown to be nested within the Phyllopsora clade and consequently was combined there (Kistenich et al. 2018). Crocynia molliuscula also belongs to Phyllopsora (Kistenich et al. 2019a) and is genetically so close to C. gossypina that the authors did not propose a new combination, awaiting further taxonomic studies of this group. porphyromelaena (Vain.) Zahlbr. Savanne: Along trail to Mt Cocotte, on bark, 2019, Ertz 23497, (TLC of both specimens: argopsin and norargopsin, solvent A). Previously reported from Piton de la Petite Rivière Noire, Macchabee Forest (0.5 1 km ESE of Macchabee Kiosk), Mt Cocotte (along path towards peak), along the road between Mt Cocotte and Bassin Blanc, and Mt Cocotte (NW of the peak), 1991, by Timdal & Krog (2001, sub P. albicans), and from the road between Mt Cocotte and Bassin Blanc, 1991, by Lücking & Timdal (2016: 194). swinscowii Timdal & Krog Mycotaxon 77: 88 (2001). Type: Mauritius, Black River, along the path from Plaine Champagne towards Piton de la Petite Rivière Noire, 1991, Krog & Timdal MAU9/50 (O L21220, holotype) (phylogeny: Kistenich et al. 2019a). Also reported from Le Pouce and from the road between Mt Cocotte and Bassin Blanc, 1991, by Timdal & Krog (2001) and Lücking & Timdal (2016: 194). PHYSCIA (Schreb.) Michx. aegialita (Afzel ex Ach.) Nyl. Dirinaria aegialita flavicans f. crocea (Ach.) Cromb. = Teloschistes flavicans obscura (Ehrh.) Hampe ex Fürnr. Reported from Mauritius by Daruty (1873). picta (Sw.) Nyl. Dirinaria picta pulverulenta (Schreb.) Hampe ex Fürnr. = Physconia distorta pulverulenta var. muscigena (Ach.) Nyl. Physconia muscigena setosa (Ach.) Nyl. = Phaeophyscia hispidula speciosa (Wulfen) Nyl. Heterodermia speciosa PHYSCIDIA Tuck. wrightii (Tuck.) Tuck. Reported from Macchabee Forest, 1991, Krog & Timdal (O, MAU) by Kistenich et al. (2018: 903). PHYSCONIA Poelt distorta (With.) J. R. Laundon [= Parmelia pulverulenta (Schreb.) Ach.; Physcia pulverulenta (Schreb.) Hampe ex Fürnr.]. Reported from Mauritius by Lindau (1908), and Sur l écorce des arbres, à l île Maurice (Bélanger 1834). muscigena (Ach.) Poelt [ Physcia pulverulenta var. muscigena (Ach.) Nyl.]. Reported from Mauritius by Daruty (1873). PHYSMA A. Massal. byrsaeum (Ach.) Müll. Arg. Plaines Wilhems: Curepipe, Curepipe Botanic Gardens, on bark, 2016, Diederich (dupl. LG); Le Pétrin, between Pétrin Information Centre and first viewpoint along trail to the west, on bark, 2016, Diederich Rivière Noire: Trail from Plaine Champagne towards Piton de la Petite Rivière Noire, on bark, 2016, Diederich (dupl. LG), (dupl. LG); ibid., 2019, Ertz 23916; Chamarel, Ebony Forest, along trail W of viewpoint, on bark, 2019, Diederich 18949; Brise Fer Forest, on bark, 2019, Diederich Savanne: Along trail to Mt Cocotte, on bark, 2019, Diederich Previously reported from Mt des Créoles, 1991, Krog & Timdal (O) by Lücking & Timdal (2016: 198) and Macchabee Forest, 1990, Hawksworth (K-IMI) Crittenden et al. (1995, as P. byrsaceum ). Further unpublished specimens from Piton de la Petite Rivière Noire, Pétrin heath and Mt Cocotte, collected by Krog & Timdal in 1991, are kept in O. byrsinum (Ach.) Müll. Arg. [ Collema byrsinum Ach.]. Reported from Mauritius by Daruty (1873). PICCOLIA A. Massal. wrightii (Tuck.) Hafellner Rivière Noire: Trail from Plaine Champagne towards Piton de la Petite Rivière Noire, on bark, 2016, Diederich PLACODIUM Weber ex F. H. Wigg. murorum DC. = Caloplaca saxicola POLYMERIDIUM (Müll. Arg.) R. C. Harris quinqueseptatum (Nyl.) R. C. Harris Plaines Wilhems: Curepipe, Trou aux Cerfs, along road surrounding the crater, on bark, 2016, Diederich 18283; Curepipe, Curepipe Botanic Gardens, on bark, 2016, Diederich 18307; ibid., 2019, Diederich 19103, 19105, & Ertz 24245, 24232; Le Pétrin, heathland NW of Pétrin Information Centre, on bark, 2019, Ertz Rivière Noire: Brise Fer Forest, on bark, 2019, Diederich The ascospores of P. quinqueseptatum are (4 )5( 7)-septate, µm, following Aptroot & Lücking (2016), respectively (4 )5 7( 8)-septate, µm, following Harris (1990). Those of the similar P. pleiomerellum are 7 11-septate, µm (Aptroot & Lücking 2016), respectively (5 )7 9( 10)-septate, µm (Harris 1990). Our specimens have 5 7( 8)-septate ascospores, mainly µm, and some are intermediate between the published descriptions of the two species. We call our material P. quinqueseptatum, as this species was known from Africa (Angola, Mozambique) and the Indian Ocean (Seychelles), while P. pleiomerellum is known only from America and Papua New Guinea (Aptroot & Lücking 2016). PORINA Müll. Arg. americana Fée. Reported from Mauritius by Crittenden et al. (1995, as Porina cf. americana). chlorotica (Ach.) Müll. Arg. [ Verrucaria chlorotica Ach.]. Reported from Rodrigues, on rocks, 1874, Balfour 2282, by Crombie (1876b). epiphylla (Fée) Fée Reported from Mauritius, on Acrostichum obductum (S F74625) by Santesson (1952: 238).

41 P. Diederich & D. Ertz: First checklist of lichens and lichenicolous fungi from Mauritius 53 Porina florensii Diederich & Ertz, sp. nov. (Figs 12 13) MycoBank MB Diagnosis: Characterized by a smooth to slightly rugulose thallus, perithecia immersed in 1 2 mm diam. convex, poorly delimited verrucae, a black ostiole, and large, mainly septate ascospores, ~ μm, with a very thick perispore, laterally ~5 7 µm, apically ~9 18 µm thick. Type: Mauritius, Rivière Noire: Black River Gorges National Park, trail from Plaine Champagne towards Piton de la Petite Rivière Noire, S (± 200 m), E (± 700 m), alt m, on bark of trees, 5 Aug. 2016, Diederich (MAU holotype, BR, herb. Diederich isotypes). Description. Thallus corticate, smooth to slightly rugulose, continuous, thin, pale olivaceous grey or green, sometimes with a narrow blackish prothallus; isidia and soralia absent. Photobiont Trentepohlia. Ascomata perithecioid, simple, dispersed, semiglobose, immersed, in ~1 2 mm diam. convex, poorly delimited verrucae, covered by a thin thallus layer, except around the ostiole; ostiole apical, blackish; wall not carbonized. Hamathecium hyaline, not inspersed, of thin, simple, μm diam. paraphyses. Asci cylindrical-clavate, I, ~ µm (n = 3), 8-spored. Ascospores hyaline, I, transversally mostly (8 )10 14( 15)-euseptate, fusiform, surrounded by a thick gelatinous sheath (perispore); measurements in water without perispore: (86 ) ( 120) (10.5 ) ( 14) µm, ratio L/B (6.8 ) ( 10.1); with perispore: (110 ) ( 153) (21 ) ( 26.8) µm, ratio (4.8 ) ( 6.0); perispore thickness laterally: (4.8 ) ( 7.7) µm; perispore apically (6 ) ( 25.8) µm (n = 20). Pycnidia not observed. Chemistry: thallus K+ reddish brown, C, KC, P, UV. No substances detected by TLC in specimen ( solvent A). Ecology and distribution. The species is known from five localities in Mauritius, where it is rather abundant and grows on trees of parks and in well-preserved forest. Notes. Amongst the similar Australian corticolous taxa keyed out by McCarthy (2001), two species have more than 7-septate ascospores: Porina bellendenica has much smaller, septate ascospores, µm, and P. internigrans has smaller, (7 )9 11( 13)-septate ascospores, µm; P. internigrans is further distinguished from the new species by a smooth to strongly rugulose-verruculose thallus and convex, hemispherical, well-delimited perithecial verrucae (e.g., see photo at Among the names that are nowadays considered to be synonyms of Porina internigrans (e.g., McCarthy 2001), P. auracariae, described from Australia, differs from the new species by shorter and broader ascospores ( µm) (Müller 1891a); P. brisbanensis, described from Australia, differs by 7 9-septate, shorter and wider ascospores (~80 16 µm) (Müller 1891a); P. exasperata, described from Australia, differs by 5 9-septate and much smaller ascospores ( µm) (Bailey 1886); and P. praestantior, described from Java, differs by slightly shorter and much wider ascospores ( µm) (Müller 1882). Most Porina species have a much thinner perispore, e.g., thin or not apparent in C. bellendenica and 2 4 µm in P. internigrans. The North American Porina rhaphidospermum has septate ascospores, which are much narrower, µm. David & Hawksworth (1995) reported Porina mastoidea agg. from Plaines Wilhems, Vacoas, Macchabee Forest, on Diospyros tesselaria, 1990, Hawksworth (K-IMI ). The detailed description and illustrations given by these authors leave little doubt that they were dealing with the same species as the new one described here. The ascospores they examined were (8 )10 12-septate, 120 (15 )17 20 µm, similar to those of our specimens. Porina mastoidea differs by smaller, 7( 8)-septate ascospores, µm (McCarthy 2001). Our phylogenetic analyses (Fig. 13) shows that the new species belongs to a clade also containing Porina alba, P. imitatrix, P. mirabilis, P. mastoidea and P. radiata, while P. internigrans is only distantly related. Etymology. The new species is dedicated to Vincent Florens, Associate Professor of Ecology and former Head of the Department of Biosciences at the University of Mauritius. He is mainly interested in the conservation of biodiversity in tropical terrestrial systems, with particular emphasis on the impact of invasive alien species on the biodiversity of tropical forests. Additional specimens examined. MAURITIUS. Plaines Wilhems: Curepipe, Curepipe Botanical Gardens, on bark, 2019, Diederich 19131; Le Pétrin, between Pétrin Information Centre and first viewpoint along trail to the west, on bark, 2016, Diederich 18348; ibid., 2019, Ertz Rivière Noire: Same locality as type, 2016, Diederich 18405, 18426; Brise Fer Forest, on bark, 2019, Diederich 19213, 19220, 19242, Savanne: Along trail to Mt Cocotte, on bark, 2019, Ertz innata (Nyl.) Müll. Arg. McCarthy (2003) erroneously reported this species from Mauritius (confusion with Reunion). mastoidea (Ach.) Müll. Arg. agg. The report of this species by David & Hawksworth (1995) almost surely refers to the newly described Porina florensii. nucula Ach. Pamplemousses: Jardin Botanique, on bark of Brownea grandiceps, 2016, Ertz tetracerae (Ach.) Müll. Arg. var. tetracerae Rivière Noire: Chamarel, Ebony Forest, close to park buildings, on bark, 2016, Diederich PSEUDEVERNIA Zopf mauritiana (Gyelnik) Dodge = Hypotrachyna microblasta PSEUDOCYPHELLARIA Vain. argyracea (Delise) Vain. Cyanisticta argyracea (Delise) Gyeln. = Sticta aspera Laurer, Linnaea 2: 41 (1827); Sticta argyracea var. aspera (Laurer) Kremp., Verh. Zool.-Bot. Ges. Wien 18: 316 (1868); Cyanisticta aspera (Laurer) C. W. Dodge, Beih. Nova Hedwigia 12: 170 (1964). Type: Mauritius, Sieber 40 (L 910, , lectotype, selected by Galloway & James 1986) (Galloway 1994: 116, 118).

42 54 Plant and Fungal Systematics 65(1): 13 75, 2020 Figure 12. Porina florensii [A: Diederich 18405; B C: Diederich 18348; D G: holotype]. A C thalli with perithecia immersed in poorly delimited verrucae; black prothallus visible in C; D section through wettened perithecium; E hymenium with mature 8-spored ascus and paraphyses, in Lugol; F lower part of hymenium, with young asci, in Lugol; G immature (below) and mature ascospores, showing perispore, in water. Scales: A C = 1 mm; D = 200 µm; E F = 20 µm; G = 10 µm. Photos: P. Diederich.

43 P. Diederich & D. Ertz: First checklist of lichens and lichenicolous fungi from Mauritius Porina mastoidea DQ Porina radiata AY Porina imitatrix KJ Porina florensii PD Porina florensii PD Porina mirabilis AY Porina alba DQ Porina karnatakensis DQ Porina tetracerae KJ Porina lucida DQ Porina epiphylla DQ Porina simulans DQ Porina guianensis DQ Porina heterospora KJ Porina cryptostoma KJ Porina subepiphylla DQ Porina nucula DQ Porina nucula KJ Porina sp. KJ Porina dolichophora KJ Porina exasperatula KJ Myeloconis erumpens KJ Myeloconis guyanensis KJ Myeloconis fecunda KJ Porina exocha KF Porina farinosa KJ Porina byssophila KR Porina chlorotica KR Porina aenea DQ Porina pacifica KT Porina rivalis KR Porina sp. KT Flabelloporina squamulifera MH Porina internigrans DQ Porina fusca DQ Porina austroatlantica KR Porina multipuncta MK Trichothelium epiphyllum AY Trichothelium pallidisetum AY Porina repanda AY Porina atrocoerulea DQ Porina papillifera DQ Porina rubescens DQ Porina nitidula KF Porina subnitidula DQ Porina lectissima DQ Porina rubentior DQ Porina limbulata AY Porina rufula DQ Coenogonium pineti AY Coenogonium luteum AY Gyalecta ulmi AY Porinaceae Figure 13. Phylogeny of Porinaceae based on a data set of mtssu sequences that resulted from a RAxML analysis. Maximum likelihood bootstrap values are shown above or near internal branches. Internal branches considered strongly supported by both the RAxML and Bayesian analyses are represented by thicker lines. The newly sequenced samples of Porina florensii are highlighted. = Stictina argyracea f. insidiata Nyl., in Crombie, J. Linn. Soc. (Bot.) 15: 435 (1876); Sticta argyracea f. insidiata (Nyl.) Zahlbr., Cat. Lich. Univ. 3: 371 (1925). Type: Rodrigues, 1874, Balfour 2279 (H-NYL 34058, holotype; BM, isotype). The holotype material in Nylander s herbarium is a small scrap taken from a larger collection in Crombie s herbarium (BM) which is preserved as two separate specimens, only one of which is numbered All three specimens are labelled f. isidiata Nyl. and not insidiata as appears in the protologue (Galloway 1994: 117). Rivière Noire: Trail from Plaine Champagne towards Piton de la Petite Rivière Noire, on bark, 2016, Diederich 18428, (dupl. LG); Chamarel, Ebony Forest, on bark, 2019, Diederich Savanne: Along trail to Mt Cocotte, on bark, 2019, Diederich 18845, 18871, 18873, 18899, 19377, & Ertz 23465, Previously also reported from Mauritius by Lindau (1908), Robillard (W) by Galloway (1994: 118), McGregor 1819 (BM) by Galloway (1994: 118), Vacquois, Ayres (BM) by Galloway (1994: 118), in Taylor herb. on sheet 450 at Harvard Univ. com. Müller Argau by Dodge (1964: 169), Macchabee Forest, 1990, Hawksworth (K-IMI) by David & Hawksworth (1995) and Crittenden et al. (1995), Bedrock ( S, E), Pétrin heath, Pétrin rainforest and Le Pouce, 2001, by Holm & Gregersen (2002), along the road between Mt Cocotte and Bassin Blanc, 1991, Krog & Timdal (O) by Lücking & Timdal (2016: 194), and from Rodrigues, 1874, Balfour 2279 (BM) by Galloway (1994:

44 56 Plant and Fungal Systematics 65(1): 13 75, ). Further unpublished specimens from Piton de la Petite Rivière Noire, Mt Corps de Garde, Macchabee Forest to Mt Brise Fer, Macchabee Kiosk and Mt Cocotte, collected by Krog & Timdal in 1991, are kept in O. aurata (Ach.) Vainio Crocodia aurata clathrata (De Not.) Malme Galloway & Arvidsson (1990: 126) reported this species from Mauritius without giving any additional information. crocata (L.) Vainio Sticta crocata L. ( )= Pulmonaria aurigera Bory, in Flörke, Mag. Neuesten Entdeck. Gesammten Naturk. Ges. Naturf. Freunde Berlin 2: 126 (1809); Cyanisticta aurigera (Bory) Dodge, Beih. Nova Hedwigia 12: 171 (1964). Type: Les arbres des forêts montagneuses des Iles de France (Mauritius) et de Mascareigne, Bory de Saint-Vincent (PC-Thuret, lectotype, fide Galloway 1988: 113) (Galloway et al. 2001: 56; Dodge 1964: ). ( )= Sticta aurigera var. nuda Delise, Hist. Lich. Sticta: 55 (1825). Type: Iles de France (Mauritius) et Mascareigne,?Bory de Saint-Vincent (PC-Thuret, lectotype, selected by Galloway & James 1986). = Sticta mougeotiana Delise, Hist. Lich. Sticta: (1825); Cyanisticta mougeotiana (Delise) Dodge, Beih. Nova Hedwigia 12: 177 (1964). Type: Ile de France, Bory de Saint-Vincent (PC-Thuret, lectotype, selected by Galloway & James 1986) (Galloway et al. 2001: 56). ( )= Sticta mougeotiana var. xantholoma Delise, Hist. Lich. Sticta: 63 (1825). Type: Insulae Borboniae ou Franciae [i.e., Reunion or Mauritius] (PC-Lenormand, lectotype, selected by Galloway & James 1986). Also reported from Mauritius, auf Rinde by Lindau (1908) and Moncada et al. (2014: 122), Wight, by Dodge (1964: 178), Sur les arbres, dans le quartier de Pampelmousses, à l île Maurice by Bélanger (1834), Pouce Mt, Ayres (BM) by Galloway (1994: 125) and Curepipe (BM) by Galloway (1994: 125). Further unpublished specimens from Mt Corps de Garde, Mt Cocotte and Curepipe Botanical Garden, collected by Krog & Timdal in 1991, are kept in O. The species was also reported from Mauritius, Søchting 30A13a (TUR) by Stenroos et al. (2006) [almost surely the same collection as the one reported by Holm & Gregersen (2002) from Pétrin heath, 2001 (C)], but Lücking et al. (2017a: 451) concluded that this specimen is best included in P. desfontainii because of the presence of laminal isidia. This specimen was sequenced and included in a phylogenetic study by Lücking et al. (2017a). desfontainii (Delise) D. J. Galloway Savanne: Along trail to Mt Cocotte, on bark, 2019, Diederich & Ertz Also reported from Mauritius, McGregor (BM), Les Mares, Ouhamed 8 (BM) by Galloway (1994: 128), Le Pouce, 2001, Søchting 30A13a p. p. (C) by Lücking et al. (2017a), Bedrock ( S, E) and Le Pouce, 2001, by Holm & Gregersen (2002). Further unpublished specimens from Piton de la Petite Rivière Noire, Le Pouce and Mt Cocotte, collected by Krog & Timdal in 1991, are kept in O. dissimilis (Nyl.) D. J. Galloway & P. James [ Stictina dissimilis Nyl.]. Reported from Rodrigues, on trees, 1874, Balfour 2277, by Crombie (1876b). dozyana (Mont. & Bosch) D. J. Galloway Savanne: Along trail to Mt Cocotte, on bark, 2019, Diederich Our specimen is rather typical, with a cyanobacterial photobiont, a white medulla, an upper uneven surface devoid of pseudocyphellae, a lower surface with white protruding pseudocyphellae, and marginal, greyish soralia distinctly eroding yellow below, and it agrees with descriptions in Galloway (1994) and Lücking et al. (2017). Additional unpublished specimens from Mt Cocotte, collected by Krog & Timdal in 1991, are kept in O. gilva (Ach.) Malme Reported from Mauritius, Blackburn (BM) by Galloway (1994: 133). intricata (Delise) Vain. Galloway (1994) indicated the presence of this species in Mauritius on a distribution map (fig. 19), but no corresponding specimen is listed under Specimens examined : possibly a lapsus for Reunion, from where the species has been described. Holm & Gregersen (2002) reported this species as Uncommon on Mauritius and La Réunion, also probably a lapsus, as their only specimen examined is from Reunion. neglecta (Müll. Arg.) H. Magn. Savanne: Along trail to Mt Cocotte, on bark, 2019, Diederich 18881, & Ertz Also reported from Le Pouce, 2001, Søchting 30A13a p. p. (C, TUR) by Lücking et al. (2017a). Our specimens perfectly agree with the description given by Lücking et al. (2017). orygmaea (Ach.) Malme [ Sticta orygmaea Ach.]. Reported from Mauritius by Laurer (1827). PSOROMA Ach. ex Michx. sphinctrinum (Mont.) Nyl. Pannaria sphinctrina PULMONARIA Hoffm. aurigera Bory = Pseudocyphellaria crocata dichotoma Bory Sticta dichotoma ( )gigantea Bory in Flörke, Magazin Ges. naturf. Fr. Berlin 2: 127 (1809). Type: An den Bäumen der Inseln Frankreich [Mauritius] und Bourbon [Reunion], Bory de Saint-Vincent (PC-Thuret, holotype). Following Galloway (1995), this is an earlier name for Sticta plumbea Delise. Galloway (1995) lectotypified the latter name on a specimen from Reunion. Following Simon et al. (2018), the species exists only in Reunion. PYRENASTRUM Eschw. americanum Spreng. = Pyrenula astroidea PYRENULA Ach. astroidea (Fée) R. C. Harris [= Pyrenastrum americanum Spreng.]. Reported from Rodrigues, on thin bark of trees, 1874, Balfour 2274 (Crombie 1876b). complanata (Mont.) Trevis. Plaines Wilhems: Le Pétrin, between Pétrin Information Centre and first viewpoint along trail to the west, on bark, 2016, Diederich

45 P. Diederich & D. Ertz: First checklist of lichens and lichenicolous fungi from Mauritius 57 confinis (Nyl.) R. C. Harris [= P. corticata (Müll. Arg.) R. C. Harris, fide Aptroot 2012]. Reported from Mauritius by Crittenden et al. (1995, as P. cf. corticata). cruenta (Mont.) Vain. Trypethelium cruentum Mont. = Trypethelium cruentulum Nyl., in Crombie, Journ. Linn. Soc., Bot. 15: 445 (1876). Type: Rodrigues, on branches of trees, 1874, Balfour 2240 (Crombie 1876b). Also reported from Rodrigues, on bark of trees, 1874, Balfour 2275 (Crombie 1876b, sub T. cruentum). fetivica (Krempelh.) Müll. Arg. =? Pyrenula truncata Müll. Arg., nom. nud.? Original material: Mt Pouce, P. B. Ayres (G ). Plaines Wilhems: Le Pétrin, between Pétrin Information Centre and first viewpoint along trail to the west, on bark, 2016, Diederich 18345, 18349; Le Pétrin, heathland NW of Pétrin Information Centre, on bark, 2019, Ertz Pyrenula truncata probably is a synonym of P. fetivica, fide Aptroot (2012). We were not able to find any paper describing P. truncata. An annotation on the specimen conserved in G says Pyrenula truncata Müll. Arg. ined., suggesting that the name has never been published. The name is also missing in the online databases Index Fungorum and MycoBank. mamillana (Ach.) Trevis. Verrucaria mamillana Ach.; = Pyrenula marginata Hook. (fide Aptroot 2012); Verrucaria marginata (Hook.) Hepp Plaines Wilhems: Le Pétrin, along trail W of Pétrin Information Centre, up to 600 m W of first viewpoint, on bark, 2019, Diederich Rivière Noire: Trail from Plaine Champagne towards Piton de la Petite Rivière Noire, on bark, 2016, Diederich 18431; Brise Fer Forest, on bark, 2019, Diederich 19210, 19223, 19437, 19427, & Ertz Previously reported Sur l écorce des arbres, à l île Maurice by Bélanger (1834) (PC ) and from Mauritius by Daruty (1873). Pyrenula muriciliata Diederich & Ertz, sp. nov. (Fig. 14) MycoBank MB Diagnosis: Characterized by a thin, brownish to greyish brown, ecorticate thallus, mm wide perithecia with an apical ostiole, and dark brown, muriform ascospores, each with a basal cilium. Type: Mauritius, Rivière Noire, Black River Gorges National Park, 5 km NW of Pétrin, Brise Fer Forest, S, E (± 200 m), alt. 585 m, on the bark of a tree, 10 Sept. 2019, Diederich (MAU, holotype; BR, herb. Diederich, isotypes). Description. Thallus ecorticate, brownish to greyish brown, continuous, very thin (20 70 µm); prothallus medium to dark brown; photobiont Trentepohlia. Ascomata perithecioid, simple, dispersed to aggregated, sometimes confluent, subspherical to conical, emergent, mm diam., black, not covered by the thallus. Wall laterally and apically more or less equally carbonized, K, 150 µm thick, basally reduced or missing. Ostiole more or less apical. Hamathecium hyaline, densely inspersed with oil droplets; paraphyses unbranched, µm thick. Asci cylindrical, I, 8 spored, µm. Ascospores when young hyaline, soon dark brown, I, muriform with 3 transverse eusepta and each row with (0 )1 longitudinal septum, ellipsoid, not or slightly constricted near septa, (13 ) ( 18) (8 ) ( 11.5) µm, ratio L/B (1.4 ) ( 1.9) (n = 53, from holotype), ends rounded, lumina rounded (best visible in hyaline young ascospores), basally with a 2 10 µm long and µm thick, straight or sometimes curved cilium. Pycnidia not observed. Chemistry: thallus K, C, KC, P, UV ; no substance detected by TLC (solvent A). Ecology and distribution. The new species is corticolous on the bark of trees in forests and parklands. It is known from three Mauritian localities (Brise Fer Forest, Pétrin, Curepipe) at m elevation. Notes. The new species differs from all known Pyrenula species by ascospores presenting a basal cilium. Aptroot (2012) reported two species with ciliate ascospores: P. ciliata Aptroot and P. hirsuta Etayo. They both differ from the new species by the presence of many hyaline cilia at both ends (vs one basal cilium) and by transseptate (vs muriform) ascospores. As the cilium may have been overlooked in other species, especially when using a microscope without DIC optics, the new species needs to be compared with similar species with muriform ascospores. Using Aptroot (2012), it keys out at Pyrenula borneensis Aptroot ined., formally described by Aptroot et al. (2012), a species readily distinguished by much larger ascospores, µm, lacking a basal cilium, and larger ascomata, mm diam. Etymology. The epithet refers to the muriform ascospores, each with a basal cilium. Additional specimens examined. MAURITIUS. Plaines Wilhems: Curepipe, Curepipe Botanic Gardens, on bark, 2016, Diederich 18296; Le Pétrin, between Pétrin Information Centre and first viewpoint along trail to the west, on bark, 2016, Diederich nitida (Weigel.) Ach. [ Verrucaria nitida (Weigel.) Schrad.]. The report from Mauritius by Daruty (1873) is erroneous, as the corresponding specimen (Daruty 63, MAU) belongs to Glyphis cicatricosa. ochraceoflava (Nyl.) R. C. Harris Moka: Réduit, State House Park, on bark, 2019, Ertz Pamplemousses: Jardin Botanique, on bark of palm tree, 2016, Diederich parvinuclea (Meyen & Flot.) Aptroot Rivière Noire: East of Black River, from Visitor s Centre to Pilgrims Trail, on bark, 2016, Diederich quassiicola (Fée) Fée = P. pinguis Fée, fide Aptroot 2012 Pamplemousses: Jardin Botanique, on bark of Brownea grandiceps, 2016, Ertz Already known from Mauritius Sur l écorce des arbres, dans la péninsule indienne et à l île Maurice (Bélanger 1834, sub P. pinguis). In the phylogenetic tree of the Pyrenulaceae (Fig. 16) our specimen is nested in a poorly resolved clade including specimens of Pyrenula

46 58 Plant and Fungal Systematics 65(1): 13 75, 2020 Figure 14. Pyrenula muriciliata [A B: holotype; C G: Diederich 18347]. A B thallus with perithecia; dark prothallus visible in A; C section through dry perithecium; D young ascus, in water; E inspersed hymenium with two asci and ascospores, in water; F 8-spored ascus and paraphyses, in water; G muriform ascospores with basal cilium, in water; young immature ascospore on bottom left. Scales: A = 1 mm; B = 500 µm; C = 200 µm; D F = 10 µm; G = 5 µm. Photos: P. Diederich. quassiicola, P. bahiana, P. sexlocularis and P. thelomorpha, while other specimens of P. quassiicola are more distantly related. As already shown by Gueidan et al. (2016), species delimitation of the widespread pantropical P. quassiicola is problematic, because the species is polyphyletic, with at least four distinct lineages highlighted in their threegene dataset. sexlocularis (Nyl.) Müll. Arg. Rivière Noire: East of Black River, from Visitor s Centre to Pilgrims Trail, on bark, 2016, Diederich PYXINE Fr. cocoes (Sw.) Nyl. Moka: Réduit, State House Park, on bark, 2019, Diederich 19288; ibid., on bark of Cinnamomum, Diederich Rivière Noire: Le Morne Peninsula, S coast, on bark, 2019, Diederich Also reported from Mauritius by Daruty (1873) and from Ile aux Aigrettes by Parnell et al. (1989) (BM, det. James). Further unpublished specimens from Yemen, Flic-en-Flac, Tamarin, Morne Brabant, Flacq and Ile aux Aigrettes, collected by Krog & Timdal in 1991, are kept in O.

47 P. Diederich & D. Ertz: First checklist of lichens and lichenicolous fungi from Mauritius 59 palmicola. A lapsus for Coccocarpia palmicola in Parnell et al. (1989: 374). petricola Nyl. ex Cromb. J. Bot. 14: 263 (1876). Type: Rodrigues, on rocks, 1874, Balfour 2391 (E, H) (Crombie 1876a, b). Reported from Ile aux Aigrettes (BM, det. James) by Parnell et al. (1989). petricola var. pallida Swinscow & Krog Rivière Noire: Le Morne Peninsula, S coast, on bark, 2019, Diederich & Ertz Our specimens have apothecia with a brownish white and K internal stipe characteristic of var. pallida (Swinscow & Krog 1975). retirugella Nyl. Rivière Noire: Chamarel, Ebony Forest, around viewpoint, on bark, 2016, Diederich Further unpublished specimens from Mt des Créoles and Ile aux Aigrettes, collected by Krog & Timdal in 1991, are kept in O. retirugella f. sorediigera Müll. Arg. Reported from Mauritius by Dodge (1971: 171). subcinerea Stirton Moka: Réduit, State House Park, on bark, 2019, Diederich 19289; ibid., on bark of Ficus microcarpa, Diederich Rivière Noire: Le Morne Peninsula, S coast, on bark, 2019, Diederich Also reported from Mt des Créoles, 1991, Krog & Timdal (O) by Lücking & Timdal (2016: 198). Further unpublished specimens from Yemen, Tamarin and Flacq, collected by Krog & Timdal in 1991, are kept in O. RAMALINA Ach. arabum (Dill. ex Ach.) Meyen & Flot. Reported from Mauritius by Daruty (1873). The corresponding specimen (Mauritius, Iles aux Aigrettes, 1873, Daruty 143, MAU L1964) was studied by Krog (1994), who confirmed its identity. calicaris (L.) Röhl. Reported from W side of Round Island, on Fernelia buxifolia (Johnston 1894: 263). As the species is unknown from Africa and Australia, this possibly refers to R. subfraxinea var. leiodea. canaliculata Taylor. Reported from Mauritius by Nylander (1870), and from Rodrigues, on branches of trees, 1874, Balfour 2210, by Crombie (1876b). A poorly known species. canaliculata f. brevior Cromb., J. Linn. Soc., Bot. 15: 434 (1876). Type: Rodrigues, on branches of trees, 1874, Balfour 2386 (Crombie 1876b). A poorly known taxon. farinacea (L.) Ach. Reported from Mauritius by Daruty (1873) and from Rodrigues, on branches of trees, 1874, Balfour 2324, by Crombie (1876b). farinacea f. pendula (Schrad.) Cromb. Reported from Rodrigues, on branches of trees, 1874, Balfour 2324b (Crombie 1876b). gracilenta (Ach.) Röhl. Reported from Rodrigues, on rocks and trees, 1874, Balfour 2283, 2297, by Crombie (1876b). gracilenta f. nodulosa Cromb., J. Linn. Soc., Bot. 15: 434 (1876). Type: Rodrigues, on rocks, 1874, Balfour 2297b (BM). A poorly known taxon. intermedia Delise ex. Nyl. Reported from Rodrigues, on rocks, 1874, Balfour 2284, by Crombie (1876b). linearis var. pumela Mont. Reported from Mauritius by Daruty (1873). A poorly known taxon. litorea N. Stevens Reported from Mauritius (saxicolous) and Rodrigues (saxicolous) (M, as R. microspora, with evernic acid) (Stevens 1986: 187; 1987: 169). maritima Krog & Swinscow. Reported from Ile aux Aigrettes, on Maytenus pyria, by Parnell et al. (1989) (BM, det. James). This species strongly resembles Ramalina subfraxinea var. leiodea (Stevens 1987: 207), and therefore the specimen might belong to that species. nervulosa (Müll. Arg.) des Abb. Moka: Réduit, State House Park, on bark, 2019, Diederich [medulla K ]; ibid., on bark of Latania lodigesii, Diederich [medulla K ]; Réduit, close to Mauritius Herbarium building, on bark, 2019, Ertz [medulla K+ pink]. Pamplemousses: Jardin Botanique, on bark, 2016, Diederich (dupl. LG) [medulla K+ pink]; ibid., on bark of Dypsis lutescens, Ertz [medulla K+ pink]; 1 km NNW of Botanical Garden, S of Museum Aventure du sucre, on bark, 2016, Diederich (dupl. LG) [medulla K ]. Previously reported from Pamplemousses Botanical Garden, 1990, Hawksworth (K-IMI) by Crittenden et al. (1995) and from the same locality, 1987, Kubodera (TNS) by Kashiwadani & Moon (2007). sprengelii Krog & Swinscow Rivière Noire: Trail from Plaine Champagne towards Piton de la Petite Rivière Noire, on bark, 2016, Diederich (dupl. LG) (specimen kept under Lichenopeltella ramalinae); ibid., 2019, Ertz 23973, 24037; Chamarel, Ebony Forest, around viewpoint, on bark, 2016, Diederich (dupl. LG); ibid., along trail W of viewpoint, on bark, 2019, Diederich subcalicaris Nyl. Reported from Mauritius (herb. Lenorm.) by Nylander (1870: 139). subfraxinea Nyl. Reported from Mauritius by Daruty (1873), Gretan (ex herb. Lenorm.) by Nylander (1870: 139), and from Rodrigues, on branches of trees, 1874, Balfour 2340, by Crombie (1876b). Probably refers to R. subfraxinea var. leiodea (Stevens 1987). subfraxinea var. leiodea (Nyl.) N. Stevens Reported from Mauritius, corticolous, Gretan (herb. Lenorm.: H-NYL or PC?) (with boninic ac.) by Nylander (1870: 139, sub R. subfraxinea) and Stevens (1987: 203, ), and from Mauritius (H-NYL 37185) (with bononic ac.) by Krog & Swinscow (1976: 167, sub R. subfraxinea; belongs to var. leiodea, fide Stevens 1987: 207). RELICINA (Hale & Kurok.) Hale limbata (Laurer) Hale [ Parmelia limbata Laurer]. Reported from Mauritius by Lindau (1908).

48 60 Plant and Fungal Systematics 65(1): 13 75, 2020 RHABDODISCUS Vain. fissus (Nyl.) Vain. Stegobolus fissus (Nyl.) A. Frisch Reported from Mauritius, 1876, Robillard (G), on the shoulder of the Pouce (BM), and Pouce, Ayres (BM) by Frisch & Kalb (2006: 460). RICASOLIA De Not. amplissima (Scop.) De Not. [= Parmelia glomulifera (Lightf.) Ach.]. Sur les rochers et sur les arbres, aux îles Maurice et de Bourbon (Bélanger 1834). crenulata var. stenospora Nyl. = Ricasolia sublaevis sublaevis Nyl. ( )= Ricasolia crenulata var. stenospora Nyl., Ann. Sci. Nat., Bot., sér. 4, 11: 254 (1859). Type: Mauritius (H-Nyl 33387, syntype, identified by I. Yoshimura as R. sublaevis. N.B.: syntype H-Nyl is not R. sublaevis and not belong to R. crenulata, fide Yoshimura, herbarium annotation) and Reunion (H-Nyl , syntype, identified by Y. Yoshimura as R. sublaevis). = Parmelia quercizans var. denudata Laurer, Linnaea 2: 40 (1827). Type: Ad arbores Insulae St. Mauritii, Sieber. This name was considered a synonym of R. crenulata var. stenospora by Dodge (1964: 158). = Lobaria wightii C. W. Dodge, Beih. Nova Hedwigia 12: 158 (1964). Type: Mauritius, Wight (FH ). Published as nom. nov. for var. denudata and var. stenospora. Also reported from Mauritius by Daruty (1873) and Hue (1892: 101). RIMELIA Hale & A. Fletcher reticulata (Taylor) Hale & Fletcher Parmotrema reticulatum subisidiosa (Müll. Arg.) Hale & Fletcher Parmotrema subisidiosum RINODINA (Ach.) Gray luridescens (Anzi) Arnold [= Lecanora coniopta Nyl.]. Reported from Rodrigues by Dodge (1971: 10). oxydata (A. Massal.) A. Massal. Reported from Moka, below Mt Ory, on shaded volcanic rocks by a track, 1990, Hawksworth (K-IMI) by David & Hawksworth (1995; agrees in all characters... except that the thallus does not react with K ) and Crittenden et al. (1995, as Rinodina cf. oxydata). ROCCELLA DC. boryi Delise ex Fée = Roccella montagnei f. teretior Cromb., J. Linn. Soc., Bot. 15: 433 (1876). Type: Rodrigues, on rocks, 1874, Balfour 2206, 2288 (BM , lectotype selected by Tehler & Irestedt 2007; BM , H-NYL 36728, H-NYL 36735, isolectotypes) (Tehler et al. 2010). = Roccella flaccida Bory, Dict. Class. Hist. Nat. 14: 631 (1828); Roccella flaccida Delise ex Darb., Biblioth. Bot. 9: 44 (1898) nom. hom. Type: Ile de France [Mauritius], 1826, Jussieu 2444 (PC, lectotype selected By Tehler & Irestedt 2007; PC, isolectotype) (Tehler et al. 2010). Also reported from Mauritius by Fée (1824: CI), from Port Louis, Mt Signal, 2003, Tehler (S, UPS), Black River, Pointe Corail de la Prairie, 2003, Tehler (S, UPS), Black River, Mt St. Pierre, the eastern peak near Bambous, ~7 km E Quatre Bornes, 2003, Tehler (S, UPS), Black River, in gorge just E of Cascavelle, ~7 km W of Quatre Bornes, on vertical cliffs, 2003, Tehler 8521 (UPS), Plaine Wilhems, Corps de Garde, 2003, Tehler (S, UPS), and Savanne, Maconde, 2003, Tehler (S), by Tehler et al. (2010). flaccida Delise = Roccella boryi fuciformis (L.) DC. Reported from Mauritius by Daruty (1873) and Sur les rochers du grand port, à l île Maurice by Bélanger (1834). fuciformis var. gracilenta Vain. ex Darb. Reported from Mauritius by Daruty (1873). mauritiana Darb. Although the epithet refers to Mauritius and a Mauritian specimen (NMW ) is annotated as isotype of R. mauritiana, this name is a nomenclatural synonym of Roccella fuciformis f. linearis and thus based on the type of the latter name from Sumatra. montagnei f. teretior Cromb. = Roccella boryi phycopsis Ach. Reported from Mauritius by Daruty (1873). tinctoria DC. Reported from Mauritius by Nylander (1859: 252). See notes under Roccellina hypomecha. tinctoria var. hypomecha Ach. Roccellina hypomecha ROCCELLINA Darb. hypomecha (Ach.) Tehler [ Roccella tinctoria var. hypomecha Ach.)]. Reported from Mauritius by Nylander (1859). Following Tehler (pers. comm.), several Mauritius specimens in PC-Delise, incorrectly identified as R. hypomecha, belong to Roccella boryi. One specimen labelled Roccella tinctoria Ile de France (S-L21425), with a handwriting resembling that of Nylander, belongs to R. hypomecha; it might have been taken by Nylander from Commerson s herbarium in Paris, where other collections state both Cap Bon de S. and Ile de France on the same label; consequently, it must be considered likely that this specimen is mislabelled and does not originate from Mauritius. ROLFIDIUM Moberg coccocarpioides (Nyl. ex Cromb.) Timdal Opera Bot. 110: 121 (1991); Lecidea coccocarpioides Nyl. ex Cromb., J. Bot., Lond. 14: 264 (1876). Type: Rodrigues, on rocks, 1874, Balfour 2219 (BM, H-NYL 13025, syntypes) (Crombie 1876a, b; Timdal 1991: 121). Rivière Noire: East of Black River, from Visitor s Centre to Pilgrims Trail, on rocks along trail, 2016, Diederich 18474; Chamarel, Ebony Forest, around viewpoint, saxicolous, on exposed rocks, 2016, Diederich (MAU); ibid., 2019, Diederich Also reported from Mt Corps de Garde, 430 m, 1991, Krog & Timdal (OMAU, O) by Kistenich et al. (2018: 904), and from continental Africa by Swinscow & Krog (1988). SAGEDIOPSIS Vain. +pertusariicola Zhurb. Rivière Noire: Trail from Plaine Champagne towards Piton de la Petite Rivière Noire, on bark, on Pertusaria sp., 2016, Diederich Zhurbenko (2009) showed that the material of Sagediopsis growing on Pertusaria slightly differs by several

49 P. Diederich & D. Ertz: First checklist of lichens and lichenicolous fungi from Mauritius 61 morphological characters from S. campsteriana (Linds.) D. Hawksw. & R. Sant., a species possibly confined to Ochrolechia, and he consequently described the new S. pertusariicola. The Mauritius specimen is in a very poor condition, with most perithecia either immature or overmature. We observed mainly immature, 1-septate ascospores, µm, and a single 2- or 3-septate ascospore, µm. These fall in the lower range of 3-septate ascospores of S. pertusariicola, given as (11 ) ( 31) (3 )4 5( 6) µm by Zhurbenko (2009). Although our specimen cannot be distinguished on a morphological basis from S. campsteriana, we include it in S. pertusariicola because of the host selection. The host is a fertile Pertusaria with apothecia immersed in convex warts, with punctiform hymenia. SARCOGRAPHA Fée tricosa (Ach.) Müll. Arg. Medusula tricosa (Ach.) Mont. Pamplemousses: Jardin Botanique, on bark of Ptychosperma macarthurii, 2016, Ertz Previously reported from Mauritius by Daruty (1873). tricosula (Nyl. ex. Cromb.) Zahlbr., Cat. Lich. Univ. 2: 467 (1923 [ 1924 ]); Glyphis tricosula Nyl. ex Cromb., J. Bot. 14: 264 (1876). Type: Rodrigues, on the thin epidermis of bark, 1874, Balfour 2363 (BM, H) (Crombie 1876a, b). SARCOGRAPHINA Müll. Arg. heterospora (Nyl.) Z. F. Jia & Lücking [ Phaeographina heterospora (Nyl.) Zahlbr.]. This species was described from Reunion but later reported by Dodge (1964: 76) as known only from Mauritius, which is most likely a lapsus. SERUSIAUXIA Ertz & Diederich, gen. nov. MycoBank MB Diagnosis: Distinguished from all known Pyrenulaceae genera by a sorediate thallus and chemistry with gyrophoric acid (C+ red soralia). Type: Serusiauxia inexpectata Ertz & Diederich. Description. See specific description below. Notes. In our phylogenetic tree (Fig. 16), this lichen is sister taxon to Lithothelium septemseptatum in a basal position within a main clade including also the genus Anthracothecium and several species of Pyrenula (including the generic type, P. nitida). This clade was defined as Pyrenulaceae, Group 1 in the phylogeny of the Pyrenulaceae by Gueidan et al. (2016). We wondered if we should include our new species within an enlarged concept of Pyrenula, which would then include the two Pyrenula clades recognized by Gueidan et al. (2016), the genus Anthracothecium and Lithothelium septemseptatum. However, the phylogenetic results strongly suggest that Pyrenula needs to be split into several genera. Pyrenulaceae, Group 1 is divided, with high support, in a clade comprising Pyrenula s.str. and Anthracothecium, and a second clade comprising our new species and Lithothelium septemseptatum. Following our tree, the two taxa are genetically rather distinct. Further, as long as the type of Lithothelium has not been sequenced, we cannot affirm that this clade refers to Lithothelium s.str. Finally, to our knowledge the new species is unique within the Pyrenulaceae by having a sorediate thallus and chemistry with lecanoric/gyrophoric acid, strongly resembling Dendrographa decolorans. We conclude that the description of a new genus Serusiauxia is the best option, supported by both molecular results and morphological characters. Etymology. Named after Emmanuël Sérusiaux (Liège, Belgium) to honour his outstanding contribution to the lichenology of tropical regions. Serusiauxia inexpectata Ertz & Diederich, sp. nov. (Figs 15 16) MycoBank MB Diagnosis: Distinguished from all known Pyrenulaceae species by a sorediate thallus and chemistry with gyrophoric acid (C+ red soralia). Type: Mauritius, Pamplemousses district, Pamplemousses, Sir Seewoosagur Ramgoolam Botanical Garden, S, E, elev. 80 m, on bark of a ± vertical trunk of Terminalia, 29 Dec. 2016, Ertz (MAU holotype, BR, herb. Diederich isotypes). Description. Thallus crustose, thin, rather inconspicuous, mostly endophloeodal, whitish to pale cream; prothallus brownish. Photobiont trentepohlioid, with cells µm. Soralia numerous, dense, punctiform when young, erumpent, flat to slightly convex with loosely heaped soredia, mostly rounded, up to 0.6 mm diam, spreading and becoming confluent, sometimes almost forming a continuous leprose crust covering large areas of the thallus, pale creamish brown, rarely pale greyish-almost white. Soredia without projecting hyphae, µm diam; hyphae µm diam covered by tiny hyaline crystals dissolving in K (polarized light!); presence of calcium oxalate crystals mostly µm diam, a few larger up to 12 µm diam (H 2 SO 4 25%!). Ascomata and conidiomata unknown. Chemistry: thallus and soralia C+ red fleeting, K± pale yellowish (weak), P, UV, I, KI. TLC revealed gyrophoric acid in solvents B and EA (specimens Ertz 21490, 21496, Diederich and tested). Ecology and distribution. The species is known from the Sir Seewoosagur Ramgoolam Botanical Garden and the Curepipe Botanic Gardens in Mauritius, where it grows on the bark of big trees, including Mangifera and Terminalia, and from the isle of Mahé in the Seychelles, where it has been collected in the Jardin du Roi parkland. Notes. The new species is most similar to Dendrographa decolorans (Arthoniomycetes), which differs by soralia with a mauve-grey to pale lilac-grey colour, different chemistry (unidentified fatty acids; thallus C ) (Wolseley & Hawksworth 2009), a non-tropical distribution (mainly in the Mediterranean and temperate regions) and a very different phylogenetic position (Arthoniomycetes, Roccellaceae) (Ertz & Tehler 2011). Sorediate morphs of Syncesia myrticola differ from the new species by a different chemistry (protocetraric acid; thallus PD+ rust-red) (Ertz et al. 2018a). Opegrapha fumosa also has a thin, inconspicuous thallus with C+ red soralia (gyrophoric acid), but the soralia are less dense, more irregular, often elliptical, and the species occurs only in temperate regions (Coppins et al. 1992). Etymology. The epithet refers to the unexpected taxonomic position within the Pyrenulaceae, despite morphological similarities with some species of Arthoniales.

50 62 Plant and Fungal Systematics 65(1): 13 75, 2020 Figure 15. Serusiauxia inexpectata [holotype]. A B thallus, showing soralia; C soredia, in K; D soredia, showing crystals formed after addition of H 2 SO 4, revealing the presence of calcium oxalate crystals. Scales: A = 2.5 mm; B = 1 mm; C = 50 µm; D = 20 µm. Photos: D. Ertz. Additional specimens examined. MAURITIUS. Pamplemousses: Same locality as type, on bark of Mangifera, 2016, Ertz 21496; ibid., 2016, Diederich Plaines Wilhems: Curepipe, Curepipe Botanic Gardens, 2019, Diederich SEYCHELLES. Mahé: W of Anse Royale, Le Jardin du Roi, parkland, on a tree, 2015, Diederich (SEY, herb. Diederich). SIPHULA Fr. mascarena Mathey Plaines Wilhems: Le Pétrin, heathland NW of Pétrin Information Centre, terricolous, 2016, Diederich 18372; ibid., 2019, Ertz 23315A (TLC: thamnolic, solvents A, B ). Savanne: Road from Le Pétrin to Chamouny, beginning of trail to Montagne Cocotte, on bark, 2016, Diederich 18378; along trail to Mt Cocotte, on bark, 2019, Diederich 18843, Previously reported from Pétrin by Mathey (1974), David & Hawksworth (1995) and Crittenden et al. (1995). SIPMANIELLA Kalb sulphureofusca (Fée) Kalb [ Lecanora sulphureofusca Fée]. Reported from Mauritius by Daruty (1873). SPHAEROPHORUS Pers. australis Laurer Bunodophoron australe compressus Ach. [as Sphaerophoron compressum ] = Bunodophoron melanocarpum SPILOMA Ach. verrucaria Ach. Sur l écorce des arbes, île Maurice (Bélanger 1834). SPIROGRAPHA Zahlbr. +lichenicola (D. Hawksw. & B. Sutton) Flakus, Etayo & Miadlikowska Cornutispora lichenicola D. Hawksw. & B. Sutton A lichenicolous pycnidial fungus reported from Mauritius, Plains, on Haematomma collatum, 1857, Ayres (BM), by Kalb et al. (1995). SPORACESTRA A. Massal. pertexta (Nyl.) Stapnes & Timdal Rivière Noire: Trail from Plaine Champagne towards Piton de la Petite Rivière Noire, on bark, 2016, Diederich 18432, (det. Timdal). SQUAMULEA Arup, Søchting & Frödén cf. squamosa (B. de Lesd.) Arup, Søchting & Frödén Rivière Noire: La Preneuse (between Tamarin and Grande Rivière Noire), cemetery (south-east part with old graves), on old tombstones from c. 1850, 2016, Diederich 18394; ibid., 2019, Diederich & Ertz 23237; Flic-en-Flac, cemetery, on historic tombs, 2019, Diederich

51 P. Diederich & D. Ertz: First checklist of lichens and lichenicolous fungi from Mauritius Pyrenula paraminarum KT Pyrenula aggregataspistea KT Pyrenula infraleucotrypa KT Pyrenula cruenta AY Pyrenula septicollaris KT Pyrenula rubrostigma KT Pyrenula mamillana KT Pyrenula inframamillana KT Pyrenula viridipyrgilla KT Pyrenula anomala KT Pyrenula anomala KT Pyrenula subpraelucida DQ Pyrenula cornutispora KT Pyrenula confinis KT Pyrenula ochraceoflava KC Pyrenula parvinuclea KT Pyrenula corticata KT Pyrenula minor KT Pyrenula aspistea KT Pyrenula aspistea KT Pyrgillus javanicus FJ Pyrgillus javanicus KT Pyrenula balia KT Pyrenula aff. mamillana JQ Pyrenula massariospora KT Pyrenula fetivica KT Pyrenula laevigata AY Pyrenula scutata KT Pyrenula nitidula KT Pyrenula subglabrata KT Pyrenula thelomorpha DQ Pyrenula quassiicola DQ Pyrenula quassiicola KT Pyrenula quassiicola s. lat. DE Pyrenula thelomorpha KT Pyrenula quassiicola KT Pyrenula sexlocularis KT Pyrenula bahiana KT Pyrenula bahiana KT Pyrenula cf. bahiana KT Pyrenula quassiicola KT Pyrenula quassiicola KT Pyrenula reebiae AY Pyrenula quassiicola KT Pyrenula subelliptica KT Pyrenula quassiicola KT Pyrenula chlorospila JQ Pyrenula macrospora JQ Pyrenula nitida DQ Pyrenula astroidea KT Anthracothecium prasinum KT Anthracothecium prasinum KT Anthracothecium prasinum KT Anthracothecium prasinum KT Anthracothecium australiense FJ Serusiauxia inexpectata DE21490 Serusiauxia inexpectata DE21496 gen. & sp. nov. Serusiauxia inexpectata PD Serusiauxia inexpectata PD17815 Lithothelium septemseptatum AY Granulopyrenis sp. DE Staurothele areolata FJ Endocarpon pusillum FJ Exophiala xenobiotica FJ Cyphellophora europaea FJ Byssochlamys nivea FJ Xeromyces bisporus FJ Pyrenulaceae Figure 16. Phylogeny of Pyrenulaceae based on a data set of mtssu sequences that resulted from a RAxML analysis. Maximum likelihood bootstrap values are shown above or near internal branches. Internal branches that are considered strongly supported by both RAxML and Bayesian analyses are represented by thicker lines. The newly sequenced samples from Mauritius are highlighted, and their names followed by collecting numbers of authors, which act as specimen and sequence identifiers. A newly sequenced sample of Granulopyrenis from Iles Éparses is also added. The length of the branches represented by dashed lines was reduced by 50% for editing reasons. mtssu and nulsu sequences clearly place our specimen within Squamulea (Fig. 10). While our mtssu sequence is identical to sequence KC from S. squamosa but differs from sequence KC of S. subsoluta by two nucleotides, our nulsu sequence differs by nine nucleotides from both species. Thus, our specimen belongs either to S. squamosa s.lat. or to a closely related, possibly undescribed species. STEGOBOLUS Mont. fissus (Nyl.) A. Frisch Rhabdodiscus fissus STEREOCAULON Hoffm. arbuscula Nyl. Lepraria arbuscula pulchellum Wedd., in Daruty, Trans. Roy. Soc. Arts Mauritius, n.s. 7: 166 (1873), nom. nud. (description missing).

52 64 Plant and Fungal Systematics 65(1): 13 75, 2020 salazinum (Bory) Fée. Reported from Mauritius, 1891, supra saxa vulcanica, fr. Rodriguez (Hue 1898). Specimen Daruty 93 (MAU L1976) from Le Pouce, sur la terre au sommet, 1873, was examined by Lamb in 1960 and annotated Stereocaulon sp., apparently related to S. sentelligerum Th. Fr. (syn. S. salazinum Bory p. p.). Too scrappy for certain identification at present. STICTA (Schreb.) Ach. Simon et al. (2018) presented a phylogenetic study of the genus Sticta in Madagascar and the Mascarenes, comprising 31 endemic species. Its diversity on Mauritius was sampled by E. Sérusiaux in Following these authors, five of the endemic species of Sticta are known from Mauritius: S. dichotoma and S. macrophylla were both described from Mauritius and are also known from Reunion; S. variabilis was described from Reunion and is also known from Mauritius and Madagascar; two further unnamed species have been recognized in Mauritius. None of these species is endemic to Mauritius. Because of the dramatic example of the tremendous impact of human contact, these authors consider that a significant part of the lichen flora in Mauritius is now extinct and our study only incorporates the few surviving taxa. The two unnamed species are called S. sp. 1 and S. sp. 10 in their phylogenetic tree. In an unpublished thesis by Simon (2015), S. sp. 1 is called Sticta pseudodiversa ad int., and S. sp. 10 is called Sticta mascarena ad int. Following that author, Sticta pseudodiversa has a thallus with rounded lobes (lobules and phyllidia lacking), lacks apothecia, and has a cyanobacterial photobiont, while S. mascarena has a thallus with elongated and dichotomously branching lobes with apothecia, and a green algal photobiont. Simon et al. (2018) stated that Five validly published epithets are available for the species studied in their paper. They obviously missed Sticta glaberrima Laurer, Stictina flavireagens Gyeln. [see comments below] and Stictina robillardii Dodge, all described from Mauritius. Three further infraspecific taxa have been described from Mauritius: Sticta damicornis var. fucoides Laurer, S. damicornis var. polita Laurer and S. dichotoma var. pendula Bory ex Delise. Duplicates of all our 2016 specimens are kept in LG, and most of these have been sequenced (indicated below by DNA followed by the sequence number). A. Simon kindly sent us identifications of the sequenced specimens. ambavillaria (Bory) Ach. Reported from Pétrin rainforest and Le Pouce, 600 m, 2001, by Holm & Gregersen (2002). argyracea Delise Pseudocyphellaria argyracea argyracea f. insidiata (Nyl. ex Cromb.) Zahlbr. = Pseudocyphellaria argyracea aspera Laurer = Pseudocyphellaria argyracea aurata Ach. Crocodia aurata aurigera var. nuda Delise = Pseudocyphellaria crocata cometia Ach. Reported from Mauritius by Laurer (1827). crocata (L.) Ach. Pseudocyphellaria crocata cyphellulata (Müll. Arg.) Hue Reported from Bedrock ( S, E) and Le Pouce, 600 m, 2001, by Holm & Gregersen (2002). Other unpublished specimens, collected by Krog & Timdal in 1991 in Mt Cocotte, Plaine Champagne towards Piton de la Petite Rivière Noire, Curepipe (Trou au Cerfs), between Pétrin and Mt Brise Fer, Macchabee Kiosk, along the road from Bois Chéri to Grand Bassin, are kept in O. damicornis (Sw.) Ach. [ damaecornis and damaecornem are orthographic variants]. Reported from Mauritius (herb. Lenormand) by Laurer (1827), Nylander (1859) and Daruty (1873), and Sur les arbres et les rochers, aux îles Maurice et de Bourbon by Bélanger (1834). Following Moncada et al. (2018), although the name Sticta damicornis has frequently been used for Sticta specimens from most continents, the species appears to occur only in the Caribbean. damicornis [as damaecornis ] var. fucoides Laurer, Linnaea 2: 42 (1827). Type: In Insula St. Mauritii, Sieber 38 p.p. (FH) (Laurer 1827, Dodge 1964: 193). damicornis var. macrophylla Nyl. Reported from Mauritius by Daruty (1873). damicornis var. polita Laurer =? Sticta dichotoma dichotoma (Bory) Delise Hist. Lich. Sticta: 107 (1825); Pulmonaria dichotoma Bory in Flörker, Magazin Ges. naturf. Fr. Berlin 2: 127 (1809). Type: An Bäumen auf der Insel Frankreich [Mauritius] und Reunion, Bory de Saint-Vincent (PC-Thuret, lectotype, selected by Galloway 1995). =? Sticta dichotoma var. pendula Delise, Hist. Lich. Sticta: 108 (1825). Type: dans les bois de l île de France [Mauritius], Bory de Saint-Vincent (PC-Lenormand, holotype) (Galloway 1995). =? Sticta damicornis [as damaecornis ] var. polita Laurer, Linnaea 2: 42 (1827); Stictina polita (Laurer) Dodge, Beih. Nova Hedwigia 12: 195 (1964). Type: In Insula St. Mauritii, Sieber, Pl. Crypt. Exot. 38 p. p. (sub. S. damaecornis var. platyphylla) (FH, ex herb. Merrill) (Dodge 1964, Laurer 1827). Following the description given by Dodge (1964), this might be a synonym of S. dichotoma. =?Sticta glaberrima Laurer, Linnaea 2: 42 (1827). Type: Ad arborem cortices Insulae St. Mauritii, 1826, Sieber (G , FH, isotypes) (Laurer 1827, Dodge 1964: 183). Following a redescription by Dodge (1964), based on the FH specimen, and a photo at bd/cjb/chg/adetail.php?id=241516&base=img&lang=en, this might be a synonym of S. dichotoma. =? Sticina robillardii Dodge [as robillardi ], Beih. Nova Hedwigia 12: 196 (1964). Type: Mauritius, Robillard (FH). Following the original description, this might be a synonym of Sticta dichotoma. Rivière Noire: Trail from Plaine Champagne towards Piton de la Petite Rivière Noire, on bark, 2016, Diederich (dupl. LG, DNA 6222). Also reported from Mauritius by Swinscow & Krog (1988), Le Pouce, 600 m, 2001, by Holm & Gregersen (2002), Mauritius, 2013, Sérusiaux 3448 (LG) by Simon (2015) and Simon et al. (2018), and Mt des Créoles, 1991, Krog & Timdal (O) by Lücking & Timdal (2016: 198). Further unpublished reliable herbarium specimens from Le Pouce (1873, Daruty, MAU L1977, det. Krog), Piton de la Petite Rivière Noire, Mt Corps de Garde, Le Pouce and Mt Cocotte, collected by Krog & Timdal in 1991, are kept in O. dichotoma var. pendula Bory ex Delise =? Sticta dichotoma faveolata var. cervicornis (Nyl.) Zahlbr. Reported from Mauritius, auf Rinde, by Lindau (1908).

53 P. Diederich & D. Ertz: First checklist of lichens and lichenicolous fungi from Mauritius 65 ( )Sticta flavireagens (Gyeln.) Diederich & Ertz, comb. nov. (Fig. 17) Basionym: Stictina flavireagens Gyeln., Repert. Spec. Nov. Regni Veg. 29: 4 (1931). Type: Mauritius, Sieber 51 (W , holotype!). MycoBank MB Description. Thallus rosette-forming to irregularly spreading, several cm diam., closely attached centrally, without basal holdfast, margins ± free, not visibly ascendant. Lobes 6 15 mm broad, at least 2 cm long, rounded, ± discrete at margins, contiguous. Margins rounded to irregular, incised, not thickened, phyllidiate and ciliate, not isidiate. Upper surface medium slate blue to olivaceous, rather even, without maculae, pseudocyphellae, isidia, phyllidia or soralia. Marginal phyllidia minute, initially almost digitiform (but not originating from isidia), soon becoming broader and flat, thallus-like, squamiform, rounded or more often incised, reaching 1 2 mm in diam. Marginal cilia sparse, ochraceous, mm long, either simple and µm thick or splitting and reaching 60 µm. Medulla white, K+ yellow (TLC not performed on type specimen). Photobiont cyanobacterial. Lower surface in marginal mm ochraceous, slightly tomentose to occasionally glabrous, ± smooth, tomentum concolorous to lower surface; centrally dark brown, densely tomentose, tomentum shaggy, densely entangled, medium to dark brown, occasionally with anchoring bundles or tufts of rhizines. Cyphellae common, round to irregular, mm diam., deeply urceolate; margins narrow, raised, sharply defined, ~20 µm thick, concolorous with lower surface, free of tomentum; basal membrane white. Apothecia not seen. Notes. Sticta flavireagens is mainly characterized by the cyanobacterial photobiont, the rosette-forming thallus without basal holdfast, the K+ yellow medulla, the absence of apothecia, the thallus surface devoid of maculae, pseudocyphellae, isidia, phyllidia or soralia, and the margin with both phyllidia and cilia. Sticta diversa (Stirt.) Zahlbr. is one of the rare species from the genus with a K+ yellow-orange medulla. The epithet pseudodiversa chosen for an undescribed species from Mauritius (Simon 2015) is based on similar morphology and chemistry. We collected several specimens in Mauritius belonging to S. pseudodiversa. As Gyelnik (1931a) described the new species S. flavireagens from Mauritius, mainly distinguished by the K+ yellow medulla, we wondered if Gyelnik s name might represent an earlier name for Simon s new S. pseudodiversa. An examination of the holotype kept in W showed a similar species, distinguished from our Mauritius specimens and from S. diversa by at least two characters: (1) marginal phyllidia are present but isidia are lacking (vs. flattened to coralloid marginal isidia are abundant); (2) the margin presents isolated cilia (such cilia are lacking in our specimens and in S. diversa). We conclude that our specimens do not belong to Sticta flavireagens. As Sieber s herbarium specimens sometimes have wrong locality annotations (e.g., see discussion under Cora gyrolophia), it is even uncertain whether Sieber s specimen originates from Mauritius, or possibly from the Antilles (as suggested for C. gyrolophia) or another country. Nevertheless, S. flavireagens seems to be a distinct species that needs to be combined in Sticta. The species should be searched for in Mauritius and in the Neotropics. Only when more specimens become available will it be possible to determine whether the annotation Mauritius is accurate or an error. Dodge (1964: 188) gave a new description of the species based on a Mauritius specimen from Sieber, kept in FH (sub S. variabilis). fragillima Bab. [ Stictina fragillima (Bab.) Nyl.] Reported from Mauritius by Daruty (1873). glaberrima Laurer =? Sticta dichotoma macrophylla Bory ex Delise in Delise, Hist. Lich. Sticta: 110 (1825); Stictina macrophylla (Bory ex Delise) Nyl., Flora 52: 111 (1869). Type: Ile de France, dans les bois assez clairs, Bory de Saint-Vincent (PC-Thuret, lectotype, selected by Galloway 1995). Rivière Noire: Trail from Plaine Champagne towards Piton de la Petite Rivière Noire, on bark, 2016, Diederich (dupl. LG, DNA 6219), (dupl. LG, DNA 6220). Previously reported from Ile de France (Mauritius), dans les bois assez clairs, 1801, by Delise (1825), Sur les rochers, aux îles Maurice et de Bourbon by Bélanger (1834), Mauritius, Robillard (FH) by Dodge (1964: 190), Le Pouce, 600 m, 2001, by Holm & Gregersen (2002), 2013, Sérusiaux 3445, 3452, 3454 (LG) by Simon (2015) and Simon et al. (2018), and Bambou Mountains and viewpoint WNW of Mt Cocotte, 1991, Krog & Timdal (O), by Lücking & Timdal (2016: 192, 194). Further unpublished reliable herbarium specimens from Piton de la Petite Rivière Noire, Le Pouce, Macchabee Forest and Macchabee Kiosk, collected by Krog & Timdal in 1991, are kept in O. macrophylla var. badia Delise [ Stictina macrophylla f. badia (Delise) Müll. Arg.]. Reported from Mauritius, Robillard (FH) by Dodge (1964: 190). mascarena Simon ined. Les photomorphes au sein des Lobariaceae (Peltigerales, Ascomycota): 9 (2015). Rivière Noire: Trail from Plaine Champagne towards Piton de la Petite Rivière Noire, on bark, 2016, Diederich (dupl. LG, DNA 6213), (dupl. LG, DNA 6214). Reported from Mauritius, 2013, Sérusiaux 3447, 3453 (LG) by Simon (2015) and Simon et al. (2018, sub Sticta sp. 10 ). mougeotiana Delise = Pseudocyphellaria crocata nylanderiana Zahlbr. = Dendriscosticta platyphylla orygmaea Ach. Pseudocyphellaria orygmaea ( )plumbea Moug. ex Delise. This species was initially described from Reunion and Mauritius ( dans les bois des îles de France et Bourbon ). Galloway (1995) lectotypified the name on a specimen from PC-Lenormand. Following Simon et al. (2018), the species exists only in Reunion. pseudodiversa Simon ined. Les photomorphes au sein des Lobariaceae (Peltigerales, Ascomycota): 9 (2015). Rivière Noire: Trail from Plaine Champagne towards Piton de la Petite Rivière Noire, on bark, 2016, Diederich (dupl. LG, DNA 6218), (dupl. LG, DNA 6217). Reported from Mauritius, 2013, Sérusiaux 3450 (LG) by Simon (2015) and Simon et al. (2018, sub Sticta sp. 1 ). pulmonacea (Ach.) Ach. = Lobaria pulmonaria rigidula Delise [ Stictina rigidula Nyl.]. Reported from Mauritius by Daruty (1873).

54 66 Plant and Fungal Systematics 65(1): 13 75, 2020 Figure 17. Sticta flavireagens [W, holotype]. A type specimen; B left thallus; C middle thallus; D right thallus; E F upper surface of thallus, showing marginal phyllidia; G lower surface of thallus, showing marginal cilia. Scales: B D = 5 mm; E G = 0.5 mm. Photos: P. Diederich.