Lindsea linduensis D.Cicuzza & M.Kessler, 2012

Lindsea linduensis D.Cicuzza & M.Kessler , sp. nov. ( Fig. 1 View FIGURE 1 ).

Type: — INDONESIA. Sulawesi: Central Sulawesi, at the border of the Lore Lindu National Park, Nokilalaki Mountain, Kulawi valley , 1200 m, 01°14'30.483" S, 120°09'19.828" E, 16 March 2008, Cicuzza 891 (holotype Z!, isotypes UC!, BO!, CEB!, GOET!) GoogleMaps .

Differs from Lindsaea repens var. sessilis by having 2-pinnate fronds (versus 1-pinnate), longer petioles (10–17 cm versus 1–5 cm), and more widely spaced ultimate segments (> 5 mm apart versus <4 mm).

Rhizomes short-creeping, 2 mm in diameter. Rhizome scales lanceolate, entire, 1.0– 1.5 mm × 0.5–0.7 mm, light brown. Petioles 10–17 cm long, ca. one third to half of the length of the lamina, 1–2 mm thick, pale green to pale brown, sharply quadrangular, adaxially channelled. Laminae bi-pinnate, oblong, shortly narrowed apically, 35–40 cm × 7–40 cm, with 1 pinna to a side. Primary and secondary rachises pale green, sharply quadrangular, proximally adaxially channelled. Pinnae ascending, 10–11 cm × 1.5–3 cm. Ultimate segments (pinnules) set apart by 5–11 mm on the rachises, sessile, spreading or slightly ascending, falcate, the apices subtruncate or narrowly rounded, the basiscopic margin concave; larger pinnules 17–19 × 4–5 mm, ca. 3–5 times longer than wide, dark green when dry, inner margins straight, quite parallel to the costae, basiscopic margins concave, acroscopic margins slightly convex, distally obliquely incised, with 7–10 incisions 0.25–1.2 mm deep, mostly progressively deeper towards the segment apices, lobes regular, rounded, ca. 1 mm wide. Terminal pinnules on each pinna gradually reduced. Veins mostly free, some vein pairs connivent near pinnule margins. Sori 7–12 per pinnule, one per lobe, 1.0– 1.5 mm long, on one or two connivent vein endings. Indusia ca. 0.25 mm wide, entire, not reaching the margins by less their width to about twice their width.

Etymology:— The specific epithet is derived from Lindu, the name of the national park close to the area where the species has been discovered. In Indonesian, the term Lindu is used to refer to earthquakes, a common occurrence in the study region, where two tectonic plates collide.

Distribution and ecology:— Lindsaea linduensis is known only from the type locality at the border on the eastern side of Lore Lindu National Park, Central Sulawesi. It was found in submontane old growth forest on Ferrasol ( FAO 2006) on metamorphic rocks in a stable, level terrain on a mid-slope. The submontane forest in the study region primarily comprises the tree families Lauraceae , Fagaceae , Sapotaceae , Moraceae and Euphorbiaceae ( Kessler et al. 2005; Culmsee & Pitopang 2009). Lindsaea linduensis was recorded only once, despite intensive collecting at this elevation at various sites within the national park and surrounding areas ( Cicuzza et al. 2010, Willinghöfer et al. 2012). It thus appears to be rare in the study region. The type was collected outside the Lore Lindu National Park, therefore without any degree of protection. The areas in and around the national park are subject to legal and illegal logging as well as a continuous expansion of the agricultural frontier ( Erasmi et al. 2010). Therefore, even if the species may not be at an immediate risk of extinction, it is likely to become so in the near future.

Notes:— Lindsaea linduensis differs from L. repens var. sessilis , the taxon to which is was recovered as genetically most similar in the phylogenetic study of Lehtonen et al. (2010), primarily by having 2-pinnate fronds (versus 1-pinnate), longer petioles (10–17 cm long versus 1–5 cm), and more widely spaced ultimate segments (> 5 mm apart versus <4 mm).

Following the keys of Kramer (1971), Lindsaea linduensis falls into group G (subg. Odontoloma Kunth ). The specimen of L. linduensis keys out to the couplet containing L. rigida and L. regularis . From these, Lindsaea linduensis differs by having less strongly creeping rhizomes, fewer pinna pairs (1 in L. linduensis , 1–7 in L. rigida , 3–9 in L. regularis ), and more sori per pinnule (7–8 in L. linduensis , 1–4 in L. rigida , 3–5 in L. regularis ).