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 and because they have been isolated for some 75 million years they now host unique vegetation types. At lower elevation (below 600 m) palms, pandans and hardwoods characterize the natural forests and can be broadly divided into coco de mer forests and sub-montane forests.
Coco De Mer Palm Forest
Forest dominated by the endemic coco de mer palm Lodoicea maldivica (Arecaceae), which incidentally has the largest seed in the world, is now largely confined to the Vallee De Mai on Praslin Island. This World Heritage sites includes several other endemic palms such as Deckenia nobilis, Nephroperma vanhoutteanum, Roscheria melanochaetes and Verschaffeltia splendida, while other endemic trees include Canthium bibracteatum (Rubiaceae), Dillenia ferruginea (Dilleniaceae), Erythroxylum sechellarum (Erythroxylaceae), Eugenia wrightii (Myrtaceae), Maba (Diospyros) sechellarum(Ebenaceae), Memecylon elaeagni (Melastomataceae) and the pandans Pandanus hornei, P. multispicatus and P. sechellarum (Pandanaceae). Common epiphytes include the ferns Asplenium nidus and Phymatodes scolopendria together with several introduced species like Philodendron. The ground layer in these forests is typically littered with the dry, dead remains of palm leaves preventing the development of an extensive ground flora. However, clumps of the endemic sedge Lophoschoenus hornei (Cyperaceae) may be found together with the strange endemic herb Hypoxidia rhizophylla (Hypoxidiaceae). The latter has tough strap-shapes leaves and a basal star-shaped flower, which varies in colour from yellow to maroon-brown.
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
Baker, J. G. 1999. Flora of Mauritius and the Seychelles. (reprint of 1877 edition). Asian Educational Services, India.
Balgooy, Van. M. M. J. 1969. A study of the diversity of island floras. Blumea, 17: 139-178.
Braithwaite, C. J. R. 1984. Geology of the Seychelles. In: Biogeography and Ecology of the Seychelles Islands. Ed. D. R. Stoddart. Dr W. Junk Publishers.
Fosberg, F. R. & Sachet, M. H. 1987. Flora of Maupiti, Society Islands. Atoll Research Bulletin, No 294.
Hemsley, W. B. 1916. Flora of Seychelles and Aldabra. Journal of Botany, 54: 1-24.
Hemsley, W. B. 1919. Flora of Aldabra: with notes on the flora of the neighbouring islands. Kew Bulletin of Miscellaneous Information, 108-153.
Hemsley, W. B. & Turrill, W. B. 1917. Plants of Seychelles and Aldabra. Journal of Botany, 55: 285-288.
Hill, M. & Currie, D. Wildlife of Seychelles. Collins Traveler’s Guide. Collins.
Hill, M. J., Vel, T. M., Holm, K. J., Parr, S. J. & Shah, N. J. 2002. Bird (Island Seychelles). Geology, Topography and Climate. Atoll Research Bulletin, No. 495: 10-28
Hill, M. J., Vel, T. M., Holm, K. J., Parr, S. J. & Shah, N. J. 2002. Conception (Island Seychelles). Geology, Topography and Climate. Atoll Research Bulletin, No. 495: 30-47.
Hill, M. J., Vel, T. M., Holm, K. J., Parr, S. J. & Shah, N. J. 2002. Cousin (Island Seychelles). Geology, Topography and Climate. Atoll Research Bulletin, No. 495: 49-70
Hill, M. J., Vel, T. M., Parr, S. J. & Shah, N. J. 2002. Curieuse (Island Seychelles). Geology, Topography and Climate. Atoll Research Bulletin, No. 495: 72-94.
Hill, M. J., Vel, T. M., Holm, K. J., Parr, S. J. & Shah, N. J. 2002. Denis (Island Seychelles). Geology, Topography and Climate. Atoll Research Bulletin, No. 495: 96-117.
Hill, M. J., Vel, T. M., Holm, K. J., Parr, S. J. & Shah, N. J. 2002. Félicité (Island Seychelles). Geology, Topography and Climate. Atoll Research Bulletin, No. 495: 118-138.
Hill, M. J., Vel, T. M., Parr, S. J. & Shah, N. J. 2002. Grand Soeur (Island Seychelles). Geology, Topography and Climate. Atoll Research Bulletin, No. 495: 140-154.
Hill, M. J., Matyot, P., Vel, T. M., Parr, S. J. & Shah, N. J. 2002. Marianne (Island Seychelles). Geology, Topography and Climate. Atoll Research Bulletin, No. 495: 156-175.
Hill, M. J., Vel, T. M., Parr, S. J. & Shah, N. J. 2002. North Island (Seychelles). Geology, Topography and Climate. Atoll Research Bulletin, No. 495: 176-199.
Hill, M. J., Vel, T. M., Holm, K. J., Parr, S. J. & Shah, N. J. 2002. Thérèse (Island Seychelles). Geology, Topography and Climate. Atoll Research Bulletin, No. 495: 200-219.
Jeffrey, C. 1968. Seychelles. In: Conservation of Vegetation in Africa south of the Sahara. Eds. I. Hedberg & O. Hedberg. Acta Phytogeogrraphica Suecica, 54: 275-279.
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.
Procter, J. 1974. The endemic flowering plants of the Seychelles - an annotated list. Candollea, 29: 345-387.
Procter, J. 1984a. Vegetation of the granitic islands of the Seychelles. In: Biogeography and Ecology of the Seychelles Islands. Ed. D. R. Stoddart. Dr W. Junk Publishers.
Procter, J. 1984b. Floristics of the granitic islands of the Seychelles. In: Biogeography and Ecology of the Seychelles Islands. Ed. D. R. Stoddart. Dr W. Junk Publishers.
Renvoize, S. A. 1979. The origins of Indian Ocean Island floras. In: Plants and Islands. Ed. D. Bramwell. Academic Press.
Stoddart, D. R. 1984. Impact of man in the Seychelles. In: Biogeography and ecology of the Seychelles Islands. Ed. D. R. Stoddart. Dr W. Junk Publishers. The Hague.
Swabey, C. 1970. The endemic flora of the Seychelle Islands and its conservation. Biological Conservation, 2: 171-177.
Walsh, R. P. D. 1984. Climate of the Seychelles. In: Biogeography and Ecology of the Seychelles Islands. Ed. D. R. Stoddart. Dr W. Junk Publishers.
White, F. 1983. The Vegetation of Africa. UNESCO.
Vesey-Fitzgerald, D. 1940. On the vegetation of Seychelles. Journal of Ecology, 28: 465-483.