Included here are the Seychelles situated in the equatorial regions of the Indian Ocean. These are the only mid-oceanic granitic islands in the world

Seychellean Montane Moss Forest

These humid moss or cloud forests are confined to the higher ridges of Mahé and Silhouette between altitudes of 550 and 880 m. Evergreen trees predominate with thick, leathery often strap-shaped leaves. The foliage often has a peculiar reddish or purplish tinge. This may include all of the leaves, as in the case of the endemic Randia ericea (Rubiaceae), or be confined to their under-surfaces as in the endemic Northea seychellarum (Sapotaceae). This together with the almost universal red bark and russet colour of epiphytic mosses gives the interior of these forests a gloomy somber appearance. Three stories can usually be distinguished. The canopy, which can reach heights of 16 m, is co-dominated by Neowormia ferruginea and Northea seychellarum. Other canopy trees include the endemic Campnospermum seychellarum (Anacardiaceae), Dillenia ferruginea (Dilleniaceae), Mimusops sechellarum (Sapotaceae), Northea hornei (Sapotaceae) and Vateria seychellarum (Dipterocarpaceae). The latter species is the only dipterocarp on the island and the only member of the Dipterocarpoidaea found outside of Australasia. A second story comprises several medium sized trees characteristic of which is the endemic palm Roscheria melanochoetes (Arecaceae), which in places can form pure stands. At higher altitudes this is typically jointed by the endemic tree Timonius sechellensis (Rubiaceae) and the two tall endemic shrubs Psychotria pervillei and P. sechellarum (Rubiaceae). However, at slightly lower elevations the main species include Colea peduculata, Randia lancifolia and the endemic Aphloia sechellensis (Aphloiaceae), Erythroxylum sechellarum (Erythroxylaceae), Eugenia wrightii (Myrtaceae), Indokingia crassa (Araliaceae), the endemic screw pines Pandanus multispicatus and P. sechellarum (Pandanaceae), and the endemic tree fern Cyathea sechellarum (Cyatheaceae). Other sub-canopy and shrub layer species include endemics like Canthium carinatum (Rubiaceae), Colea seychellarum (Bignoniaceae), Craterispermum microdon (Rubiaceae), Drypetes riseleyi (Putranjivaceae), Ficus bojeri (Moraceae), Gastonia sechellarum (Araliaceae), Gynura seychellensis (Asteraceae), Ixora pudica (Rubiaceae), Pittosporum wrightii (Pittosporaceae), Roscheria melanochaetes (Arecaceae), Tarenna sechellensis (Rubiaceae), Timonius sechellensis (Rubiaceae) and Verschaffeltia splendida (Arecaceae). At ground level, ferns such as Dryopteris wardii, Lindsaya kirkii, Nephrolepis biserrata, Polystichum adiantiforme and Vittaria scolopendrum are particularly prominent. Among the flowering plants there are beds of the endemic Curculigo sechellensis (Hypoxidaceae) and clumps of the endemic sedge-like Thoracostachyum floribundum (Cyperaceae). Other endemic herbs are Begonia seychellensis (Begoniaceae), Protarum sechellarum (Araceae), Thoracostachyum angustifolium (Cyperaceae), the pitcher plant Nepenthes pervillei (Nepenthaceae) and the rare saprophyte Seychellaria thomassetii (Triuridaceae).

Seychellean Sub-Montane Forest

At lower elevations below the moss forest where the soils tend to be deeper, and mist and cloud less frequent, a taller more species rich forest is thought to have been widespread at one time, but much of this has now been destroyed. None of the original canopy appears to be intact, but it seems likely that it mainly comprised Neowormia ferruginea and the endemic Northea seychellarum (Sapotaceae) and Vateria sechellarum (Dipterocarpaceae). It is also not now possible to ascertain whether there were three or four stories, although much of the remaining evidence suggests the latter. Today conspicuous elements of the second story are the endemic Campnosperma sechellarum (Anacardiaceae) and the palm Verschaffeltia spendida (Arecaceae), both of which do not extend into the moss forest. Less frequent second story species are Brexia madagascariensis, Riseleya griffithii and the endemic Craterispermum microdon (Rubiaceae), Soulamea terminalioides (Simaroubaceae) and Tarenna sechellensis (Rubiaceae). The third story comprises small trees and saplings although there appear to be few if any species that only grow at this level. The endemic palms Nephrosperma vanhoutteana, Phoenicophorium sechellarum and Rosheria melanochaeta (Areaceae) commonly occur while other species include the endemic Canthium bibracteatum (Rubiaceae), Erythroxylum sechellarum (Erythroxylaceae), Indokingia crass (Araliaceae), Ixora pudica (Rubiaceae) and Maba (Diospyros) sechellarum (Ebenaceae). The fourth or ground layer comprises various herbs notably Begonia aptera and the endemic Impatiens gordoni (Balsaminaceae) and Senecio sechellensis (Asteraceae). The epiphytic flora is well developed but has fewer species than the moss forest and festoons of moss are absent. Lianas, on the other hand, are scarce although the endemic Geopanax procumbens (Araliaceae) is relatively common on Silhouette. On certain ridges of Mahé the two endemic trees Excoecaria benthamiana (Euphorbiaceae) and Mimusops sechellarum (Sapotaceae) form what appears to be a local association, while on several rocky knolls such as ‘sugar loaf’ hill above Grande Anse on Mahé, the endemic palm Deckenia nobilis (Arecaceae) characterizes another local association. The latter formation possibly represents an outlier of the palm forests of Praslin.

References

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Matatiken, D. & Dogley, D. 2005. Guide to Endemic Palms and Screw Pines of the Seychelles Granitic Islands. Plant Conservation Action Group, Victoria, Mahé, Seychelles.

Procter, J. 1973. National Parks in Seychelles. Biological Conservation, 5: 153-155.

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