This art icle was downloaded by: [ 104.241.64.18] On: 12 March 2015, At : 11: 17 Publisher: Taylor & Francis I nform a Lt d Regist ered in England and Wales Regist ered Num ber: 1072954 Regist ered office: Mort im er House, 37- 41 Mort im er St reet , London W1T 3JH, UK New Zealand Journal of Botany Publicat ion det ails, including inst ruct ions f or aut hors and subscript ion inf ormat ion: ht t p: / / www. t andf online. com/ loi/ t nzb20 Rain forest vegetation of 'Eua Island, Kingdom of Tonga Donald R. Drake Clyde T. Imada a b , Timot hy J. Mot ley c , W. Art hur Whist ler c & d a Biology Depart ment , Georgia Sout hern Universit y , Landrum Box 8042, St at esboro, GA, 30460, USA b School of Biological Sciences , Vict oria Universit y of Wellingt on , P. O. Box 600, Wellingt on, New Zealand c Bot any Depart ment , Universit y of Hawai'i , Honolulu, HI 96822, USA d Bot any Depart ment , Bernice P. Bishop Museum , P. O. Box 19000A, Honolulu, HI 96817, USA Published online: 07 Dec 2011. To cite this article: Donald R. Drake , Timot hy J. Mot ley , W. Art hur Whist ler & Clyde T. Imada (1996) Rain f orest veget at ion of 'Eua Island, Kingdom of Tonga, New Zealand Journal of Bot any, 34: 1, 65-77, DOI: 10. 1080/ 0028825X. 1996. 10412694 To link to this article: ht t p: / / dx. doi. org/ 10. 1080/ 0028825X. 1996. 10412694 PLEASE SCROLL DOWN FOR ARTI CLE Taylor & Francis m akes every effort t o ensure t he accuracy of all t he inform at ion ( t he “ Cont ent ” ) cont ained in t he publicat ions on our plat form . However, Taylor & Francis, our agent s, and our licensors m ake no represent at ions or warrant ies what soever as t o t he accuracy, com plet eness, or suit abilit y for any purpose of t he Cont ent . Any opinions and views expressed in t his publicat ion are t he opinions and views of t he aut hors, and are not t he views of or endorsed by Taylor & Francis. 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Term s & Condit ions of access and use can be found at ht t p: / / www.t andfonline.com / page/ t erm sand- condit ions New Zealand Journal of Botany, 1996, Vol. 34:65-77 0028-825X/96/3401M?65 $2.50/0 9 The Royal Society of New Zealand 1996 65 Downloaded by [104.241.64.18] at 11:17 12 March 2015 Rain forest vegetation of 'Eua Island, Kingdom of Tonga DONALD R. DRAKE Biology Department Georgia Southern University Landrum Box 8042 Statesboro, GA 30460, USA Present address: School of Biological Sciences, Victoria University of Wellington, P. O. Box 600, Wellington, New Zealand ridges and shrub-dominated vegetation of cliffs and rocky shores, were sampled semi-quantitatively and are also described. Keywords 'Eua; Pacific Islands; rain forest; Tonga; flora; vegetation INTRODUCTION W. ARTHUR WHISTLER TIMOTHY J. MOTLEY Botany Department University of Hawai'i Honolulu, HI 96822, USA CLYDE T. IMADA Botany Department Bernice P. Bishop Museum P. O. Box 1900(~A Honolulu, HI 96817, USA Abstract The indigenous vegetation o f ' E u a Island, Tonga, is described and a species list presented. Quantitative data were collected from 40 forest plots in which all vascular plant species were recorded and the diameters of all stems >_ 5 cm dbh were measured. Plot classification, based on basal area data, identified six forest types, two coastal and four inland, which reflect an elevational sequence from the coast to the island's summit (312 m a.s.l.). A polar ordination, based on basal area data, arranged plots from the four inland forest types in a sequence from low to high elevation along one ordination axis, and from more mature to less mature along a second axis. Species richness increased with elevation. Several additional, non-forest vegetation types, including fern- and grass-dominated vegetation of inland B95023 Received 17 May 1995; accepted 27 October 1995 The Kingdom of Tonga consists of two parallel chains of islands that run roughly north and south, between 15-23 ~ S latitude and 173-176 ~ W longitude in the South Pacific Ocean (Fig. 1). The sparsely-inhabited western chain consists of relatively young, active, mainly andesitic volcanoes up to 1030 m a.s.1. The densely-inhabited eastern chain consists of older, raised limestone islands up to 312 m a.s.1. To date, there have been few published descriptions of the vegetation of Tonga. Uhe (1974) and Sykes (1981) have described the vegetation of the volcanic islands of Niuafo'ou and Late, respectively. The coastal communities of several small islets in the Tongatapu (Stoddart 1975; Ellison 1990) and Ha'apai (Woodroffe 1983) groups have been described. Palmer (1988) surveyed the least disturbed relictual stand of inland forest on the limestone island of Tongatapu. Straatmans (1964) and Sykes (1978) have published brief, qualitative descriptions of the vegetation of'Eua, which is Tonga's highest, oldest, and least disturbed large, limestone island. Whistler (1992) has reviewed the vegetation of Samoa and Tonga. Although 'Eua has long been reputed to support the richest, most unique forest in Tonga (Sykes 1978), no detailed, quantitative description of'Eua's forest vegetation has ever been published. The rapid rate of forest clearing on 'Eua has recently begun to threaten its remaining stands of indigenous forest (Allen 1990), increasing the need for such a description for scientific and conservation purposes. The purpose of this study was to describe the composition and distribution of the indigenous vegetation of Downloaded by [104.241.64.18] at 11:17 12 March 2015 66 Fig. 1 Map of the major islands of Tonga and of the five physiographic provinces on 'Eua (after Hoffmeister 1932) : 1) the eastern terraces and coastal region, 2) the eastern ridge, 3) the dissected, western slope of the eastern ridge, 4) the western ridge and central valley, and 5) the western slope terraces and coastal region. 'Eua. A summary of the preliminary analysis of the data (Drake et al. 1990) was supplied to the Tongan Government and was used as a basis for establishing a national park on 'Eua in 1992. New Zealand Journal of Botany, 1996, Vol. 34 1). East of the ridge, a series of steep cliffs, interrupted by narrow terraces, leads to the coast. Much of the terraced relief is the result of periodic, geologic uplifting of the island. Hoffmeister (1932) mapped five physiographic provinces on 'Eua: 1) the eastern terraces and coastal region, 2) the eastern ridge, 3) the dissected, western slope of the eastern ridge, 4) the western ridge and central valley, and 5) the western slope terraces and coastal region. Although most of its surface is covered by limestone, 'Eua is unique among Tonga's limestone islands in that its core consists of volcanic rocks, and these form exposed outcrops along the eastern ridge and eastern cliffs (Hoffmeister 1932; Bryan et al. 1972). Overlying the core, and forming additional outcrops along the eastern ridge and its margins, is a layer of Eocene foraminiferal and algal limestones. Overlying the Eocene limestones on the eastern ridge and its western slopes are Miocene submarine tufts and tuffaceous limestone. Late Tertiary coral reef limestone comprises the bulk of the western ridge and central valley, and forms minor terraces along both coasts. Quaternary andesitic tephra forms a layer up to 2 m thick over most of the island, except in steep areas where it has been removed by erosion. Most soils are derived from the young andesitic tephra with or without additional volcanic alluvium from older tephras (Wilde & Hewitt 1983). Deeplyweathered soils from the tufts comprising the core are found where the core forms outcrops along the eastern ridge. Volcanic and calcareous parent materials combine to form colluvial soils on steep slopes and at the bases of cliffs. Elsewhere, calcareous materials are not involved in soil formation, except as unconsolidated sand along the coasts. Development of distinct soil horizons decreases, and evidence of continual soil development due to downslope movement increases, with increasing steepness of slope. The majority o f ' E u a ' s soils are alfisols and mollisols, with inceptisols on the steep (> 30 ~ slopes and entisols (coralline sands) along some coasts (Wilde & Hewitt 1983). Climate STUDY AREA Geology and soils 'Eua is a high island, roughly 81 km 2 in area, whose surface rises gradually from the west coast as a series of distinct terraces, to a high eastern ridge with a maximum elevation of 312 m a.s.1. (Hoffmeister 1932; Bryan et al. 1972; Wilde & Hewitt 1983) (Fig. 'Eua lies within the south-east tradewind zone, and winds blow from the easterly quadrant 65-75% of the time. Mean annual rainfall is approximately 2700 mm, of which roughly 2A falls during the wet season of November to April (Thompson 1986). There is little seasonal variation in temperature. Sykes (1978) has remarked that the microclimate near the summit ridge appears cooler and moister than that at lower elevations. Drake et al.--Forest vegetation of 'Eua Island, Tonga 67 METHODS Downloaded by [104.241.64.18] at 11:17 12 March 2015 Data collection In June and July 1990, forest vegetation was sampled in forty 600 m 2 plots (mainly 20 • 30 m), each located in a stand of forest representative of that found in the surrounding area. Stands that had obviously been disturbed by humans were avoided. For each plot, the precise location (on topographic map and aerial photo), elevation, aspect, slope, substrate (bare sand, limestone, volcanic soil), and canopy height were determined and all vascular plant species were recorded. A species list is presented in Appendix I. For all trees, diameters of all stems _> 5 cm diameter at breast height (dbh) were measured. For individuals < 5 cm dbh, as well as shrubs, herbs, epiphytes, and lianas, a Braun-Blanquet semiquantitative estimate of cover was made for each species in each of several strata: shrub (c. 1-3(-5) m), ground cover (< 1.0 m), epiphyte, and liana (Mueller-Dombois & Ellenberg 1974). BraunBlanquet, semi-quantitative cover estimates were also made in seven 600 m 2 plots in non-forest vegetation. Detailed notes on species distribution and forest composition were also compiled for sites not sampled quantitatively. Most of the plots were located in the most extensive tracts of undisturbed forest along the eastern coast and terraces, the eastern ridge, and the steep ravines of the western slope of the eastern ridge. A few additional plots were located in smaller, disjunct stands of indigenous vegetation scattered throughout the island. Data analysis Relative basal area data for the 86 tree species recorded in the 40 plots that were sampled quantitatively were analysed using two-way indicator species analysis (TWINSPAN, Hill 1979) to identify species associations. Relative basal area data for 35 inland forest plots were also analysed using a Bray-Curtis polar ordination (ORDIFLEX, Gauch 1979) to identify gradients in species composition. The five coastal forest plots on coralline sands and raised limestone benches were excluded from the ordination because their dissimilarity to the 35 inland plots resulted in poor separation among the inland plots. End points of the first axis were the two plots that were most dissimilar to each other; end points of the second axis were the two remaining plots that were most dissimilar to each other and had first axis scores between 40 and 60. 3O 31 ~ 2 I ,, le 35 26 6-24 5 7 - - 8 16 19 V 22 28 29 33 37 38 --40__ 4 t 21 8 2 IV 9 13 ~, 14 17 10 26 U 34 39 , a~ J.k_ ; Level 3 o Elevation (m) Fig. 2 Dendrogram derived from two-way indicator species analysis (TWINSPAN) classification of 40 forest plots, using relative basal area of tree species. Roman numerals represent the following vegetation types: I. Excoecaria-Tournefortia coastal forest, II. HernandiaTerminalia coastal forest, III. Maniltoa-Pleiogynium lowland rain forest, IV. Myristica lowland rain forest, V. Calophyllum mixed upland rain forest, VI. CalophyllumGarcinia upland rain forest. The elevational range over which each type occurs is indicated at the right. RESULTS TWINSPAN identified six ecologically interpretable groups of plots at the third level of classification, with the three largest groups being divided into three additional subtypes at the fourth level (Fig. 2). One plot (no. 34), containing a large, outlying coastal tree, was misclassified by TWINSPAN and, in the community descriptions below, is grouped based on its 68 position in the ordination. In general, TWINSPAN ordered the plots into groups reflecting a topographic sequence from the coast to the summit ridge. Characteristics of the six community types and their variants are outlined below. In the following descriptions, species within a given stratum are listed in order of decreasing relative basal area (trees) or Braun-Blanquet cover values (smaller species). For the dominant species, mean relative basal area (rba) and maximum dbh are given in parentheses (% rba, diam. cm). New Zealand Journal of Botany, 1996, Vol. 34 occurs in the canopy in places. The subcanopy is overwhelmingly dominated by Neisosperma oppositifolium, which can occasionally exceed 50 cm dbh, plus lesser amounts o f Cordia subcordata (only on the northwest coast), and Grewia crenata. A lower stratum contains Pandanus tectorius, Xylosma simulans, Cycas rumphii, and Vavaea amicorum. The only common terrestrial herb is the fern Phymatosorus grossus, and epiphytes are rare. Lianas are sparse, the most common ones being Epipremnum pinnatum, Hoya australis, Faradaya amicorum, and Jasminum didymum. Downloaded by [104.241.64.18] at 11:17 12 March 2015 I. Excoecaria-TourneJortia coastal forest is found at elevations < 5 m a.s.1, on raised limestone substrates that lack sand or soil. It exists in small, disjunct patches that combine to form a narrow band along the coast, though they rarely extend more than 20 m inland. There is often no beach along the seaward margin of these forest patches, and therefore exposure to waves and salt spray, particularly during storms, must be great. Species richness is low. Excoecaria agallocha (48%, 69 cm) and Tournefortia argentea (syn. Argusia argentea) (40%, 75 cm) dominate the canopy. Both are multistemmed trees that reach a height of 12 m. Hibiscus tiliaceus, another multi-stemmed tree, forms a somewhat lower middle stratum, which often includes Neisosperma oppositifolium, Schleinitzia insularum, and Morinda citrfolia. The shrub stratum contains scattered individuals of Bikkia tetrandra, Wollastonia biflora, Clerodendrum inerme, and Scaevola sericea, all of which are much more abundant in the strand vegetation (type VII) on the seaward margin of this forest. Terrestrial herbs, epiphytes, and lianas are rare. II. Hernandia-Terminalia coastal forest is found at elevations < 5 m a.s.1, on sand substrates. Although this forest is somewhat sheltered behind sand beaches and strand vegetation, it is presumably strongly influenced by salt spray, and occasionally by large storms such as cyclone 'Ofa, which had obviously disturbed the understory of many littoral forest sites in January 1990. Species richness is greater than in the Excoecaria-Tournefortia coastal forest. The upper canopy is dominated by Hernandia nymphaeifolia (31%, 90 cm) and/or Terminalia catappa (25%, 122 cm). Other common, large (> 40 cm dbh) canopy trees include Terminalia litoralis, Guettarda speciosa, Planchonella grayana, Schleinitzia insularum, Hibiscus tiliaceus, Myristica hypargyraea, and Pisonia grandis; Cocos nucifera III. Maniltoa-Pleiogynium lowland rain forest occurs only in the north-western quarter of the island along the western slope terraces and coastal region. This vegetation begins at the landward edge of the littoral forest, where sand or exposed limestone gives way to volcanic soils overlying limestone, and continues inland up to elevations of 60 m, on slopes ranging from 11-20 ~ Here Myristica hypargyraea and Neisosperma oppositifolium, the dominant species of lowland rain forests over the rest of the island (see below), are completely absent. Instead, the dominant species are Maniltoa grandiflora (49%, 56 cm) and Pleiogynium timoriense (17%, 56 cm). Other large trees (> 35 cm dbh) include Sapindus vitiensis and Aleurites moluecana. The subcanopy contains Chionanthus vitiensis, Xylosma simulans, Vavaea amicorum, and Diospyros samoensis. A lower stratum contains Cryptocarya hornei, Cycas rumphii, Memecylon vitiense, Micromelum minutum, Rhamnella vitiensis, and the shrub Graptophyllum insularum. The most common terrestrial herb is Asplenium polyodon. Lianas comprise 29% of the species in the flora and are abundant, especially Entada phaseoloides, Jasminum simplicifolium, Alyxia stellata, Jasminum didymum, Gynochtodes epiphytica, and Malaisia scandens. IV. Myristica lowland rain forest begins at the landward edge of the coastal forest, where sand or exposed limestone gives way to volcanic soils overlying limestone, and continues inland up to elevations of 110 m, on slopes ranging from 0-33 ~ or more. It is found along the eastern slopes and terraces, western slope terraces, and coastal region, everywhere except in the north-western quarter of the island. Myristica hypargyraea (53%, 97 cm) is the overwhelming dominant in this forest type, where no other species averages more than 13% rba. It is a Drake et al.--Forest vegetation of 'Eua Island, Tonga large tree, reaching a height of 25 m, and is usually present in all size classes. Occasional large (> 40 cm dbh) individuals of Pleiogynium timoriense, Downloaded by [104.241.64.18] at 11:17 12 March 2015 Maniltoa grandiJTora, Guettarda speciosa, Canarium harveyi, Diospyros samoensis, Planchonella grayana, and Calophyllum neoebudicum are also scattered through this forest type. The subcanopy contains Neisosperma oppositifolium and Xylosma simulans. A lower stratum often includes Diospyros samoensis, Hibiscus tiliaceus, Citronella samoensis, Cycas rumphii, and the shrub Macropiper puberulum. Herbaceous species are uncommon, with little cover. Asplenium australasicum is occasionally present as an epiphyte. Lianas comprise 25% of the flora, the most abundant species being Faradaya amicorum, Connarus sp. nov., Epipremnum pinnatum, A lyxia bracteolosa, Entada phaseoloides, Jasminum simplieifolium, Gynochtodes epiphytica, and Jasminum didymum. In places (plots 9, 14), this forest type appears to be in a state of recovery from some past disturbance; here the leading dominant is Dendrocnide harveyi (57%, 112 cm). Dendroenide harveyi saplings do not occur in the understory beneath a closed canopy of mature trees. Myristica hypargyraea is codominant in the upper stratum and abundant in the lower strata. V. Calophyllum mixed upland rain forest occurs on volcanic soils overlying the limestone of the upper eastern terraces, the western slope of the eastern ridge, and upper portions of the ridge and ravine system of the central valley, at elevations of 100180(-240) m, on slopes of2~45 ~ The tree strata are quite rich here, and no one species comprises, on average, more than 12% of the relative basal area in this forest. O f the 15 plots classified into this type, eight different species were the leading dominant in at least one plot, and no one species was the leading dominant in more than three plots. The most consistently abundant large tree is Calophyllum neo-ebudicum (11%, 91 cm); it is present in all plots, reaches a height of 35 m, and is typically represented in all size classes. Dysoxylum tongense (12%, 171 cm) is the most common co-dominant, and is present in 80 % of the plots. Other common canopy species (> 50 cm dbh) are Elattostachys falcata, Canarium harveyi, Myristica hypargyraea, Alphitonia zizyphoides, Maniltoa grandiflora, Neonauclea forsteri, Semecarpus vitiensis, Litsea mellifera, and Dysoxylum forsteri. The subcanopy contains large amounts of Diospyros samoensis, Cryptocarya hornei, Garcinia myrtifolia, and Citronella samoensis. The lower stratum includes 69 Vavaea amicorum, Cryptocarya turbinata, Hedycarya dorstenioides, and Psychotria carnea, and large amounts of the shrub Macropiper puberulum. The herb layer is well-developed, and is dominated by the ferns Tectaria dissecta, Christella parasitica, Pteris comans, and A rachnoides aristata; the ground orchid Corymborkis veratrifolia is also common. Asplenium australasicum is occasionally present as an epiphyte. Lianas comprise 23% of the flora and are extremely abundant, especially Entada phaseoloides, Alyxia bracteolosa, Embelia vaupelii, Jasminum simplicifolium, Connarus sp. nov., Epipremnum pinnatum, Melodinus vitiensis, Jasminum didymum, and Gynochtodes epiphytica. In places, this forest type appears to be in a state of recovery from some past disturbance, and here the leading dominants are either Dendrocnide harvevi (55%, 95 cm) with Bischofiajavanica (24%, 56 cm) (plots 7 and 8), or Rhus taitensis alone (65%, 99 cm) (plots 6, 23, and 24). Where present, these species combine to form > 65% of the relative basal area, though they are absent from all smaller size classes, which are instead dominated by the other tree species common to the Calophyllum mixed forest. VI. Calophyllum-Garcinia upland rain forest occurs on volcanic soils overlying limestone, at elevations of 190-300 m, on slopes of 5-40 ~ It is found upslope of the Calophyllum mixed forest and reaches its greatest development mainly on the steep slopes near the summit of the eastern ridge. Here, in contrast to the Calophyllum mixed forest below, the upper canopy is more strongly and consistently dominated by Calophyllum neoebudicum (27%, 76 cm), which is typically represented in all size classes. Other common large (> 40 cm dbh) trees include Neonauclea forsteri, Homalium whitmeeanum, Canarium harveyi, Podocarpus pallidus, Dysoxylum tongense, Elaeocarpus graeffei, Hernandia moerenhoutiana, Myristica hypargyraea, and Rhus taitensis. The subcanopy is almost completely dominated by Garcinia myrtifolia (15%, 32 cm), which can occur at densities of more than 50 trees per plot; it is consistently represented in all size classes. The lower stratum contains Vavaea amicorum and the shrubs Macropiper puberulum, Ixora ealcicola, Cordyline fruticosa, and Phaleria glabra. The herbaceous layer is well-developed and the most common elements are the ferns Arachnoides aristata, Pteris comans, Schizaea dichotoma, and Christella parasitica. Asplenium australasicum and Robiquetia bertholdii are common epiphytes. Lianas are extremely abundant, 70 especially Faradaya amicorum, Smilax vitiensis, Alyxia bracteolosa, Jasminum simplicifolium, Freycinetia urvilleana, Alyxia stellata, Hoya australis, and Embelia vaupelii. In places (plots 2, 18, 35) where this forest type appears to be in a state of recovery from some past disturbance, the leading dominants are Alphitonia zizyphoides (33%, 76 cm) and Elattostachysfalcata (11%, 48 cm). These are absent from the smaller size classes, which are instead dominated by the other tree species common to Calophyllum-Garcinia forest. Alphitonia zizyphoides is less common outside disturbed upland forest, but E.falcata is often present in low numbers throughout the upland rain forest. New Zealand Journal of Botany, 1996, Vol. 34 Axis 2 100 24 6 23 2 75 18 8 40 35 50 16 * 15 Downloaded by [104.241.64.18] at 11:17 12 March 2015 25 Other types of vegetation, sampled semi-quantitatively, include: VII. Strand vegetation: The species composition of the strand vegetation, like that of the adjacent coastal forest, is determined largely by the substrate. Seaward of the Excoecaria-Tournefortia coastal forest, and elsewhere on other bare, raised limestone benches, the vegetation consists of a shrubby layer dominated by Bikkia tetrandra, Scaevola sericea, Clerodendrum inerme, and Wollastonia biflora, with a ground layer of succulent species such as Pemphis acidula, Sesuvium portulacastrum, and the parasitic vine Cassythafil(formis. Seaward of the HernandiaTerminalia coastal forest, on sand, trees include scattered individuals of Cocos nuc~'ra, Tournefortia argentea, Acacia simplex, and Sophora tomentosa. The most common shrubs are Scaevola sericea and Wollastonia bilTora, and the ground layer contains Ipomoeapes-caprae. On some sandy shores, the tree Schleinitzia insularum forms small, monospecific stands. VIII. Cliff vegetation: The upper cliffs of the eastern ridge are covered in many places by a smooth canopy of wind-swept vegetation, 3-6 m high. Common species include Diospyros elliptica, Citronella 17 4 \ 0 0 I 25 30 38 3 7 [ '%,1 50 I I 75 100 .Axis 1 Fig. 3 Bray-Curtis polar ordination of 35 inland forest plots of "Eua, using relative basal area of tree species. Roman numerals represent the following vegetation types: III. Maniltoa-Pleiogynium lowland rain forest, IV. Myristica lowland rain forest, V. Calophyllum mixed upland rain forest, VI. Calophyllum-Garcinia upland rain forest. IX. Monospecific clonal stands: At lower and middle elevations, Hibiscus tiliaceus often forms extensive (> 1000 m2), nearly monospecific stands that appear to have arisen through clonal growth. The stands are characterised by numerous stems growing in many planes and creating dense thickets. At middle and high elevations, multi-stemmed, clonal individuals of the banyan Ficus obliqua occasionally cover areas in excess of 1000 m 2, to the exclusion o f most other woody species. The upper branches of the banyans support large numbers of the fern Asplenium australasicum. X. Toafa (treeless) vegetation: Toafa vegetation samoensis, Maesa tongensis, Badusa corymbifera, occurs on deeply weathered soils on exposed, volMaytenus vitiensis, and many others. At lower eleva- canic ridges. Although the exact composition of the tions, where the eastern cliffs are very steep and toafa patches varies from place to place, the physirelatively exposed to salt spray, the vegetation is ognomy is very consistent. A mixture of grasses, open-canopied and dominated by Pandanus pteridophytes, and scattered woody species forms an tectorius, and, in the south-east, by Pritchardia upper stratum 0.5-1.5 m tall, beneath which numerpacifica. Where the cliffs are less steep, though still ous herbaceous and semi-woody species are found. exposed to spray, there is a low forest of Hibiscus Common species include the grasses Miscanthus tiliaceus, Myristica hypargyraea, Neisosperma floridulus and Paspalum conjugatum, the pteridooppositifolium, Pandanus tectorius, Terminalia phytes Dicranopteris linearis, Sphaerostephanos catappa, Schleinitzia insularum, and Cycas rumphii. unitus, and Lycopodium cernuum, and the woody Drake et al.--Forest vegetation of 'Eua Island, Tonga 71 5O 7o I 40 60 I y = 0.77(x)+ 25.4 i . .430 "~20 r~"40 lO ~-ao N 0 9 5099 100"149150199200"249 >249 Elevation (m) 9 " .. * . 10 I , 9 2 : "- 0 " 50 I I M. hypargyraea [ ] C. neo-obudicum Downloaded by [104.241.64.18] at 11:17 12 March 2015 .. 20 <50 Fig. 4 . Basal area of two dominant species of trees (Myristica hypargyraea and Calophyllum neo-ebudicum) at various elevations. (Community types IV, V, and VI, only; number of plots = 3, 3, 6, 10, 7, and 3, from left to right). 100 150 200 Elevation (m) 250 300 Fig. 5 Regression of species richness (number of vascular plant species per 600 m~plot) vs. plot elevation for the 40 forest plots on 'Eua. DISCUSSION 'Eua supports a variety of plant communities; some are relatively widespread throughout Western Polyspecies Wikstroemia foetida, Alphitonia zizyphoides, nesia, while others may be found nowhere else in the Psidium guajava, and Melastoma denticulatum. The Pacific. In general, 'Eua's coastal vegetation is similar to mean number of species in five 600 m e plots was that found in strand habitats throughout the tropical 26.4. South Pacific. Species such as Hernandia nymphaeiTrends folia, Terminalia spp., Tournefortia argentea, and Results of the ordination corresponded well with the Scaevola sericea are common coastal dominants TWINSPAN analysis. Three of the major inland elsewhere in Tonga (Stoddart 1975; Woodroffe communities were spread, with little overlap, along 1983; Ellison 1990), as well as in Nauru and Kiribati the first axis (Fig. 3). An exception was one inland (Thaman 1992), Tuvalu (Woodroffe 1986, 1991), community (Maniltoa-Pleiogynium lowland forest), Wallis, Futuna, and Aloft (Morat & Veillon 1985), which appeared at the center of the ordination, be- Fiji (Garnock-Jones 1978; Kirkpatrick & Hassall cause it lacked the dominant species of the plots that 1981; Ash 1992), Samoa (Whistler 1980, 1983), Tokelau (Parham 1971), and the Cook Islands (Merformed the end points. The first axis score was positively correlated with lin 1991; Franklin & Merlin 1992). In contrast, elevation (first axis ordination score = 0.24 • plot Excoecaria agallocha appears to be of limited imelevation (m) + 15.3, n = 35, r 2 = 0.52, P < 0.001). portance outside Tonga. Similarly, the treeless, toafa vegetation dominated This trend is further illustrated by the shift in dominance from Myristica hypargyraea to Calophyllum by ferns (e.g., Dicranopteris tinearis) and grasses neo-ebudicum with increasing elevation in commu- (e.g., Miscanthus floridulus) frequently noted on nities IV, V, and VI (Fig. 4). Species richness in the 'Eua (Straatmans 1964; Sykes 1978; Whistler 1992) forest plots increased with increasing elevation (n = is also common on poor, volcanic soils elsewhere in 40, r 2 = 0.38, P < 0.001; Fig. 5), with plots near the the South Pacific. It occurs in Vanuatu (Schmid summit of the eastern ridge having approximately 1975), Wallis, Futuna, and Aloft (Morat & Veillon twice as many species as occurred in plots near sea 1985), Fiji (Garuock-Jones 1978; Ash 1992), Samoa level. The second ordination axis appeared to cor- (Whistler 1980), the Cook Islands (Sykes 1978; respond to degree of disturbance, with vegetation Merlin 1985, 1991), and the Society Islands (Fosberg subtypes judged to be recovering from some past 1992). 'Eua's secondary forests share many pioneer spedisturbance occurring high on the second axis, and cies with disturbed forests of other islands. For exolder stands occurring lower (Fig. 3). 72 Downloaded by [104.241.64.18] at 11:17 12 March 2015 ample, Alphitonia zizyphoides, Rhus taitensis, and Elattostachysfalcata are among the dominants on the relatively young volcanic island of Late, and the latter two are dominant in the last relictual stand of inland forest on the limestone island of Tongatapu (Palmer 1988). Straatmanns (1964) first described the dynamic relationship among 'Eua's canopy trees. He noted that seedlings ofA. zizyphoides, R. taitensis, and E. falcata did not grow in dense forest, whereas seedlings of Calophyllum neo-ebudicum and Myristica hypargyraea did. In addition, A. zizyphoides, R. taitensis, and E. falcata, together with Dendrocnide harveyi and Bischofia javanica, are important components o f secondary forests in Vanuatu (Schmid 1975), Wallis, Futuna, and Aloft (Morat & Veillon 1985), and Samoa (Whistler 1980). In contrast to the secondary forests, 'Eua's oldgrowth inland rain forests bear little similarity to those of other regional islands. Several factors may account for the uniqueness of 'Eua's rain forests. Because the number of plant taxa in the Pacific generally decreases with increasing distance from Malesian source areas (van Balgooy 1971; Fosberg 1984; Stoddart 1992), nearly every island or small archipelago has a somewhat unique flora and, therefore, vegetation. Large islands north and west of Tonga contain many of the dominant species of 'Eua's mature rain forest, however, these species are not dominant in these richer forests. For example, Samoa's Syzygium lowland forest is dominated by Syzygium inophylloides (uncommon on 'Eua), but also contains substantial amounts of two Tongan dominants, Myristica hypargyraea and Calophyllum neo-ebudicum (Whistler 1992). In upland forests on Mt. Korobaba, Fiji, Calophyllum neo-ebudicum and Garcinia myrtifolia are common, but not dominant (Kirkpatrick & Hassall 1985). Islands east of Tonga, such as the Cook Islands, simply lack many of the Yongan dominants (Merlin 1985, 1991; Franklin & Merlin 1992). Stoddart (1992) states that "there is no more dramatic biogeographic boundary in the Pacific than that between the southern Cooks and the southern Tongan islands." This discontinuity is at least partly a reflection of 'Eua's position on the eastern margin of the continental Indian-Australian Plate. Other, non-biogeographic factors also contribute to 'Eua's uniqueness. Due to their combination of limestone substrate, elevation, and relief, raised limestone islands such as 'Eua, Makatea, and Mangaia tend to have distinctive floras (Stoddart 1992). As a result, their vegetation bears little New Zealand Journal of Botany, 1996, Vol. 34 similarity to that of nearby volcanic or low coral islands. Thus, 'Eua's forests differ from those of the volcanic islands in Tonga, such as Late. Sykes ( 1981) noted Casuarina equisetifolia, A Iphitonia zizyphoides, Elattostachys falcata, and Rhus taitensis as dominant and Calophyllum neo-ebudicum as common on Late; in contrast, Myristica hypargyraea, Maniltoa grandiflora, Dysoxylum spp., and Garcinia myrt~folia were absent. Even among raised limestone islands, 'Eua is relatively unique in its combination of great elevation (312 m a.s.l.), large surface area (81 km2), age (Eocene), sharp relief, deep andesitic soils, and volcanic core. Only 'Uta Vava'u in northern Tonga has the proper combination of biogeographic position, size (95 km2), elevation (210 m), and andesitic soils over limestone (Orbell et al. 1985) to potentially support rain forest vegetation similar to 'Eua's. However, 'Uta Vava'u's vegetation is quite distinct because many of the dominant species of ' E u a ' s forests are rare or absent there (J. Franklin & D. Drake unpubl, data). Given the uniqueness o f ' E u a ' s rain forest vegetation, the Tongan Government deserves praise for the foresight they have demonstrated through their ongoing efforts to protect a large tract of it in a national park. ACKNOWLEDGMENTS This study was funded by a grant from the Pacific Islands Development Program and the Program on the Environment of the East-West Center in Honolulu, Hawaii. The Tongan Government, including the Ministry of Agriculture, Forestry, and Fisheries and the Ministry of Lands and Surveys facilitated our efforts throughout the project. M. Pomelile, M. Thomas, M. Sau, and K. Siakumi provided valuable assistance in the field. The manuscript benefitted greatly from the critical comments of J. Ash, J. Franklin, F. Kell, A. McGee, and an anonymous reviewer. REFERENCES Allen, R. B. 1990: Tongan forestry subsector study. Unpublished report. Christchurch, Forest Research Institute. Ash, J. 1992: Vegetation ecology of Fiji: Past, present, and future perspectives. Pacific science 46:111127. van Balgooy, M. M. J. 1971: Plant-geography of the Pacific. Blumea supplement 6: 1-222. Downloaded by [104.241.64.18] at 11:17 12 March 2015 Drake et a l . - - F o r e s t vegetation o f 'Eua Island, Tonga Bryan, W. B.; Stice, G. D.; Ewart, A. 1972: Geology, petrography, and geochemistry of the volcanic islands of Tonga. Journal o f geophysical research 77: 1566-1585. Drake, D. R.; Hamilton, L.; Thomas, P. 1990: Report on a biological survey of 'Eua Island, Tonga, and a proposal for a national park. Honolulu, East-West Center. Ellison, J. C. 1990: Vegetation and floristics of the Tongatapu outliers. Atoll research bulletin 332: 1-36. Fosberg, F. R. t984: Phytogeographic comparisons of Polynesia and Melanesia. In: Radovsky, F. J.; Raven, P. H.; Sohmer, S. H. ed. Biogeography of the tropical Pacific. Lawrence, Association of Systematics Collections and the Bernice P. Bishop Museum. Pp. 33~J,4. Fosberg, F. R. 1992: Vegetation of the Society Islands. Pacific science 46: 232~50. Franklin, J.; Merlin, M. 1992: Species-environment patterns of forest vegetation on the uplifted reef limestone ofAtiu, Mangaia, Ma'uke and Miti'aro, Cook Islands. Journal of vegetation science 3: 3 14. Garnock-Jones, P. J. 1978: Plant communities on Lakeba and southern Vanua Balavu, Lau Group, Fiji. Royal Society of New Zealand bulletin 17: 95117. Gauch, H. G., Jr. 1979: O R D I F L E X - A flexible computer program for four ordination techniques: WEIGHTED AVERAGES, POLAR ORDINATION, PRINCIPAL COMPONENTS ANALYSIS, and RECIPROCAL AVERAGING Release B. Ithaca, New York, Section of Ecology and Systematics, Cornell University. Hill, M. O. 1979: T W I N S P A N - A FORTRAN program for arranging multivariate data in a two-way table by classification of the individuals and attributes. Ithaca, New York, Section of Ecology and Systematics, Cornell University. Hoffmeister, J. E. 1932: Geology of'Eua, Tonga. Bishop Museum bulletin 96" 1-93. Kirkpatrick, J. B.; Hassall, D. C. 1981: Vegetation of the Sigatoka sand dunes, Fiji. New Zealand journal o f botany 19: 285-297. Kirkpatrick, J. B.; Hassall, D. C. 1985: The vegetation and flora along an altitudinal transect at Mount Korobaba, Fiji. New Zealand journal of botany 23: 33-46. 73 Morat, P.; Veillon, J.-M. 1985: Contribution /i la connaissance de la v6g6tation et de la flore de Wallis et Futuna. Adansonia 3: 259-329. Mueller-Dombois, D.; Ellenberg, H. 1974: Aims and methods of vegetation ecology. New York, John Wiley. Orbell, G. E.; Rijkse, W. C.; Laffan, M. D.; Blakemore, L. C. 1985: Soils of part Vava'u Group, Kingdom of Tonga. New Zealand soil survey report 66: 148. Palmer, M. W. 1988: The vegetation and anthropogenic disturbance of Toloa Forest, Tongatapu Island, South Pacific. Micronesica 21: 279-281. Parham, B. E. V. 1971: The vegetation of the Tokelau Islands with special reference to the plants of Nukunonu atoll. New Zealand journal o f botany 9: 576q509. Schmid, P. M. 1975: La flore et la vdgetation de la pattie m6ridionale de l'Archipel des Nouvelles Hebrides. Philosophical transactions Of the Royal Society of London, series B 272: 329-342. Smith, A. C. 1979, 1981, 1985, 1988, 1991: Flora vitiensis nova: a new flora ofFiji. Vols 1-5. Lawai, Pacific Tropical Botanical Garden. Stoddart, D. R. 1975: Sand cays of Tongatapu. Atoll research bulletin 181:1-15. Stoddart, D. R. 1992: Biogeography of the tropical Pacific. Pacific science 46: 276-293. Straatmans, W. 1964: Dynamics of some Pacific island forest communities in relation to the survival of the endemic flora. Micronesica 1:113-122. Sykes, W. R. 1978: The pteridophytes of 'Eua, southern Tonga. Royal Society o f New Zealand bulletin 17: 119-152. Sykes, W. R. 1981: The vegetation of Late, Tonga. Allertonia 2: 323-353. Thaman, R. R. 1992: Vegetation of Nauru and the Gilbert islands: case studies of poverty, degradation, disturbance, and displacement. Pacific science 46: 128-158. Thompson, C. S. 1986: The climate and weather of Tonga. New Zealand Meteorological Service miscellaneous publication 188. Wellington. Uhe, G. 1974: The composition of the plant communities inhabiting the recent volcanic ejeeta of Niuafo'ou, Tonga. Tropical ecology 15:126-139. Wagner, W. L.; Herbst, D. R.; Sohmer, S. H. 1990: Manual of the flowering plants of Hawai'i. Honolulu, Bernice P. Bishop Museum. Bishop Museum special publication 83. Merlin, M. D. 1985: Woody vegetation in the upland region of Rarotonga, Cook Islands. Pacific science 39: 81-99. Whistler, W. A. 1980: The vegetation of Eastern Samoa. Allertonia 2:45-190. Merlin, M. D. 1991: Woody vegetation on the raised coral limestone of Mangaia, southern Cook Islands. Pacific science 45:131-151. Whistler, W. A. 1983: Vegetation and flora of the Aleipata Islands, Western Samoa. Pacific science 37: 227249. 74 New Zealand Journal of Botany, 1996, Vol. 34 Whistler, W. A. 1991: The ethnobotany of Tonga: the plants, their Tongan names, and their uses. Bishop Museum bulletin in botany 2:1 155. Whistler, W. A. 1992: Vegetation of Samoa and Tonga. Pacific science 46:159-178. Wilde, R. H.; Hewitt, A. E. 1983: Soils of 'Eua Island, Kingdom of Tonga. New Zealand soil survey report 68: 1~42. Woodroffe, C. D. 1986: Vascular plant species-area relationships on Nui atoll, Tuvalu, Central Pacific: a reassessment of the small island effect. Australian journal of ecology 11: 21-31. Woodroffe, C. D. 1991. Vegetation of Tuvalu. South Pacific journal of natural science 11: 82-128. Yuncker, T. G. 1959: Plants of Tonga. Bishop Museum bulletin 220: 1-283. Woodroffe, C. D. 1983: The impact of cyclone Isaac on the coast of Tonga. Pacific science 3 7:181-210. Downloaded by [104.241.64.18] at 11:17 12 March 2015 APPENDIX I List of vascular plants recorded in the vegetation samples Since there is no recent treatment of the spermatophyte flora of Tonga, nomenclature follows several sources. Smith (1979, 1981, 1985, 1988, 1991) treats nearly all of the spermatophyte species. For species not treated by Smith, the most recent treatment from among Yuncker (1959), Wagner et al. (1990), or Whistler (1991) is followed. Nomenclature for pteridophytes follows Sykes (1978). Tongan names are from Yuncker (1959), Sykes (1978), Whistler (1991), and the present study. Voucher specimens are deposited in the personal collection of A. Whistler at the University of Hawai'i (UHAW). Key: E = endemic, I = indigenous, P-- Polynesian introduction, A = post-European introduction. PTERIDOPHYTES Adiantaceae Hymenophyllaceae Trichomanes humile, I Trichomanes sax!fragoides, I Lindsaeaceae Sphenomeris chinensis, I Lycopodiaceae Lycopodium cernuum, hiku 'i pusi, I Marattiaceae Angiopteris evecta, hulufe vai, I Polypodiaceae Drynaria rigidula, I Phymatosorus grossus, I Pyrrosia adnascens, I Psilotaceae Psilotum nudum, I Schizaeaceae Schizaea dichotoma, masalu ngaue, I Thelypteridaceae Aspidiaceae Christella parasitica, I Sphaerostephanos decadens, I Sphaerostephanos invisus, I Sphaerostephanos unitus, I Arachnoides aristata, hulufe leisi, I Tectaria dissecta, I Tectaria latifolia, I Antrophyum plantagineum, I GYMNOSPERMS Aspleniaceae Cycadaceae Pteris comans, I Pteris ensiformis, I Pteris tripartita, I Vittariaceae Cycas rumphii, longolongo, I Asplenium australasicum, hakato, I Asplenium marattioides, I Asplenium polyodon, I Loxoscaphe gibberosum, hulufe leisi, I Podocarpus pallidus, uhiuhi, E DICOTYLEDONS Athyriaceae Acanthaceae Podocarpaceae Diplazium harpeodes, I Graptophyllum insularum, I Blechnaceae Aizoaceae Blechnum orientale, I Cyatheaceae Sphaeropteris lunulata, ponga, ! Davalliaceae Davallia solida, kulutuma, I Nephrolepis hirsutula, hulufe, I Dennstaedtiaceae Microlepia speluncae, I Gleicheniaceae Dicranopteris linearis, kahiva'e, I Sesuvium portulacastrum, I Amaranthaceae Achyranthes aspera, tamatama, I or P Deeringia amaranthoides, I Anacardiaceae Pleiogynium timoriense, tangato, I Rhus taitensis, tavahi, I Semecarpus vitiensis, blahi, I Apiaceae Centella asiatica, tono, A Drake et a l . - - F o r e s t vegetation o f ' E u a Island, T o n g a Apocynaceae Aly~:ia bracteolosa, kulu, I Alyxia stellata, maile, I Cerbera odollam, toto, I EJwatamia obtusiuscula, te'ete'emanu, I Melodinus vitiensis, tuamea, I Neisosperma oppositfolium, fao, I Dichapetalaceae Dichapetalum vitiense, kili, I Ebenaceae Diospyros elliptica, k~nume, I Diospyros major, mapa, 1 Diospyros samoensis, tutuna, kokau 'uli, I Araliaceae Elaeocarpaceae Me~ta macrophylla, ku|ukulu, I Polyseias multij'uga, tanetane vao, I Elaeocarpus graeffei, ma'ama'alava, I Elaeocarpus sp. nov., E Elaeocarpus tonganus, ma'ama'alava, I Asclepiadaceae Hoya australis, laumatolu, I Hoya pottsii, I Tylophora samoensis, I Asteraceae Downloaded by [104.241.64.18] at 11:17 12 March 2015 Stictocardia tiliifolia, A Ageratum conyzoides, A Bidens pilosa, fisi 'uli, A Conyza bonariensis, A Elephantopus mollis, A Emilia sonchifolia, A Sonchus oleraceus, A Synedrella nodiflora, pakaka, A Vernonia cinerea, fisi puna, A Wollastonia biflora, ate, I Euphorbiaceae Aleurites moluccana, tuitui, P Bischofiajavanica, koka, I Chamaesyce atoto, I Chamaesyce hirta, A Croton microtiglium, I Drypetes vitiensis, I Excoecaria agallocha, feta'anu, I Glochidion ramiflorum, malolo, I Macaranga harveyana, loupata, I Omalanthus nutans, fonua mamala, I Phyllanthus amicorum, E Flacourtiaceae Barringtonia asiatica, futu, I Homalium whitmeeanum, I Xylosma simulans, filimoto, I Boraginaceae Gesneriaceae Tournefortia argentea, touhuni, I Cordia aspera, tou, I Cordia subcordata, pua taukanave, I Goodeniaceae Barringtoniaceae Cyrtandra samoensis, I Scaevola sericea, ngahu, I Burseraceae Hernandiaceae Canarium harveyi, 'ai, I Caesalpiniaceae Hernandia moerenhoutiana, pipi tui, I Hernandia nymphaeifolia, fotulona, I Maniltoa grandiflora, tautau 'a manu, pekepeka, I Hippocrataceae Campanulaceae Salacia pachycarpa, I Wahlenbergia marginata, I Icacinaceae Caricaceae Citronella samoensis, olavai, I Carica papaya, lesi, A Lauraceae Cassythaceae Cryptocarya hornei, motou, I Cryptocarya turbinata, kakala 'uli, motou, I Litsea mellifera, mamea, ! Cassythafiliformis, fatai, I Casuarinaceae Casuarina equisetifolia, toa, I Loganiaceae Celastraceae Fagraea berteroana, pua, I Geniostoma rupestre, te'epilo 'a maui, I Maytenus vitiensis, I Clusiaceae Loranthaceae Calophyllum inophyllum, feta'u, I Calophyllum neo-ebudicum, tamanu, I Garcinia myrtifolia, feto'umaka, I Decaisninaforsteriana, topu'uno, kainikavea, I Lythraceae Pemphis acidula, ngingie, I Combretaceae Malvaceae Lumnitzera littorea, I Terminalia catappa, telie, I Terminalia litoralis, telie 'a manu, I Abelmoschus moschatus, P Hibiscus tiliaceus, fau, I Sida rhombifolia, te'ehoosi, P Thespesia populnea, milo, I Connaraceae Connarus sp. nov., vavatu, E Rourea minor, va'a 'uli, I Convolvulaceae Ipomoea indica, fue 'ae puaka, I Ipomoea macrantha, fue hina, I Ipomoea pes-eaprae, fue kula, I Merremia peltata, fue mea, I Operculina ventricosa, fue hina, A Meliaceae Aglaia heterotricha, langakali vao, E Dysoxylumforsteri, mo'ota hina, I Dysoxylum tongense, mo'ota mea, mo'ota kula, E Vavaea amicorum, ahi vao, I Melastomataceae Melastoma denticulatum, I Memecylon vitiense, malamala 'a toa, I 75 76 Menispermaceae Pachygone vitiensis, ! Pittosporum arborescens, masi kona, I Pittosporum yunckeri, E Mimosaceae Rhamnaceae Acacia simple.,:, tat~ngia, I Adenanthera pavonina, A Entada phaseoloides, sipi, I Mimosa pudica, mateloi, A Schleinitzia insularum, feifai, I Alphitonia zizyphoides, toi, I Colubrina asiatica, fiho'a, I Rhamnella vitiensis, I Rosaceae Osteomeles anthyllidifolia, I Monimiaceae Rubiaceae Hedycarya dorstenioides, I Antirhea inconspicua, I Bikkia tetrandra, siale tafa, I Cyclophyllum barbatum, I Geophila repens, tono, I Guettarda speciosa, puopua, I Gynochtodes epiphytica, I Hedyotis Jbetida, I Ixora calcicola, ola, I Morinda citrifolia, nonu, I Morinda myrtifolia, mamange, I Mussaenda raiateensis, monomono 'a hina, I Neonaucleaforsteri, afa, I Psychotria carnea, I Psychotria leiophylla, I Psydrax odorata, olamaka, I Spermacoce assurgens, 'aselemo, A Tarenna sambucina, rnanonu, I Moraceae Ficus obliqua, 'ovava, I Ficus prolixa, 'ovava, I Ficus scabra, masi 'ata, I Ficus tinctoria, masi 'ata, I Malaisia scandens, hiehieapo, I Streblus anthropophagorum, I Downloaded by [104.241.64.18] at 11:17 12 March 2015 N e w Z e a l a n d Journal o f Botany, 1996, Vol. 34 Myristicaceae Myristica hypargyraea, kotone, I Myrsinaceae Discocalyx listeri, E Embelia vaupelii, I Maesa tongensis, I Myrtaceae Decaspermumfruticosum, nukonuka, l Psidium guajava, kuava, A Syzygium brackenridgei, fekika vao, I Syzygium dealatum, fekika vao, ! Syzygium quadrangulatum, I Syzygium richii, heavula, I Nyctaginaceae Pisonia grandis, puko, I Pisonia umbellOCera, I Olacaceae Anacolosa lutea, I Oleaceae Chionanthus vitiensis, 'afa, I Jasminum didymum, tutu 'uli, I Jasminum simplicifolium, tutu 'uli, I Onagraceae Rutaceae Melicope retusa, I Micromelum minutum, takafalu, I Santalaceae Santalum yasi, ahi, I Sapindaceae Elattostachysfalcata, ngatata, ngatata kula, I Guioa lentisc(folia, E Harpullia arborea, filiamaama, I Sapindus vitiensis, ngatata hina, | Sapotaceae Burckella richii, kau, I Planchonella garberi, kalaka, I Planchonella grayana, kalaka, I Ludwigia octovalvis, A Solanaceae Oxalidaceae Capsicumfrutescens, polo, polo fifisi, A Solanum amicorum, I Solanum mauritianum, pula, A Oxalis corniculata, kihikihi, P Papilionaceae Canavalia cathartica, I Canavalia sericea, fue veli, I Desmodium triflorum, A lnocarpusfagifer, ifi, I or P Mucuna gigantea, valai, I Pueraria lobata, aka, A Sophora tomentosa, lata, I Strongylodon sp. nov., matafu'i, I Vigna marina, lautolu tahi, I Passifloraceae Passiflora maliformis, vaine tonga, A Passiflora subpeltata, A Peperomiaceae Surianaceae Suriana maritima, ngingie, I Thymelaeaceae Phaleria glabra, I Wikstroemiafoetida, lala vao, I Tiliaceae Grewia crenata, fo'ui, ! Triumfetta procumbens, I Ulmaceae Celtis harperi, I Trema cannabina, mangele, I Urticaceae Piperaceae Dendrocnide harveyi, salato, I Pipturus argenteus, 'olong~t, I Procris pedunculata, I Macropiperpuberulum, kavakava'ulie, I Verbenaceae Pittosporaceae Clerodendrum inerme, tutu hina, tutu tahi, I Peperomia tutuilana, ! Drake et a l . - - F o r e s t vegetation o f ' E u a Island, T o n g a Faradaya amicorum, fufula, I Lantana camara, talatala, A Premna serrat(folia, volovalo, I Stachytarpheta urticifolia, hiku 'i kum~., A Violaceae Melicytus samoensis, I MONOCOTYLEDONS Agavaceae CordylineJkuticosa, I or P Furcraeafoetida, faumalila, A Araceae Amorphophallus paeoniifolius, teve, P Epipremnum pinnatum, Alu, I Arecaceae Cocos nucifera, niu, I Pritchardia pacifica, piu, I Downloaded by [104.241.64.18] at 11:17 12 March 2015 Commelinaceae Rhoeo spathacea, faina kula, A Cyperaceae FimbrisWlis cymosa, I FimbrisO,lis ovata, I Mariscus sumatrensis, A Scleria polycarpa, mahelele, I Dioscoreaceae Dioscorea bulb(fera, hoi, I Liliaceae Dianella aff. intermedia, lave'imoa, I Liparis disepala, I Malaxis latisegmenta, I Malaxis resupinata, I Phaius tankarvilleae, I Robiquetia bertholdii, I Spathoglottis plicata, lave'i moa, I Taeniophyllum Jasciola, I Pandanaceae Freycinetia urvilleana, | Pandanus tectorius, I Poaceae Botriochloa bladhii, A Chrysopogon aciculatus, matapekepeka, P Cyrtococcum oxyphyllum, P Digitaria ciliaris, A Imperata conferta, 1 Ischaemum murinum, I Lepturus repens, I Miscanthusfloridulus, kaho tonga, I Oplismenus compositus, mohuku laukofe, P Panicum decompositum, A Paspalum conjugatum, vailima, A Paspalum vaginatum, A Stenotaphrum micranthum, I Thuarea involuta, kefukefu, I Smilacaceae Smilax vitiensis, matafu'i, I Orchidaceae Taccaceae Corymborkis veratrifolia, I Goodyera rubicunda, I Hetaeria whitmeei, 1 Zingiberaceae Tacca leontopetaloides, mahoa'a, P Zingiber zerumbet, angoango, P 77