Included here is Cook Island of Tahiti, the Line Islands, Marguesas Islands, Mangarera Islands, Society Islands, Tubuai Islands, Tuamotus Islands (such as Pitcairn and Henderson Islands), Ducie Island, Easter Island, Rapa Island and Sala-Y-Gomez.

Polynesian Limestone Plateau Forest

Forest covers much of the elevated limestone plateau of Henderson Island. In places it forms a closed-canopy dominated by Pisonia grandis, but with a wide range of associated species including the endemic Celtis pacifica (Ulmaceae), Glochidium pitcairnensis (family?) and Xylosma suaveolens (Salicaceae). However, many of the trees are partially decumbent and the canopy height is never more than about 10 m, but with occasional emergents like Guettarda speciosa and Pandanus tectorius. Lianas, including Morinda myrtifolia, are common and a rich shrub layer includes Cyclophyllum barbatum, Psydrax odorata and the endemic Ixora fragans (Rubiaceae). The herb layer is usually well developed and includes Asplenium nidus, Phymatosorus scolopendria, and the endemic Peperomia hendersonensis (Piperaceae). In fissured and pinnacled areas the endemic Hernandia stokesii (Hernandiaceae) becomes more conspicuous, while on the poorer soils the forest are more open. Here Xylosma suaveolens becomes co-dominant with Pisonia grandis and the endemic Bidens hendersonensis (Asteraceae) and Santalum insulare (Santalaceae) are more common. In places, such as around the plateau margins the forest gives way to thicket in which Cyclophyllum barbatum, Nephrolepis hirsutula, Psydrax odorata, Timonius polygamus and the endemic Geniostoma hendersonense (Loganiaceae) usually predominate.

Polynesian (Makatea) Limestone Vegetation

This is named after Makatea Island (northern Tuamotus) and refers to the vegetation of rugged limestone of elevated atolls. There are usually concentric rings of coastal makatea with the vegetation becoming richer away from the coast. It can also be found on Atiu, Mangaia, Ma’uke and Mitiàro (Cook Islands) and the Plateau of Henderson Island (southern Tuamotus). Here it consists of a low tangle of shrubs dominated by Timonius polygamus. Other shrubs include dwarf versions of Cassytha filiformis, Cyclophyllum barbatum, Phymatosorus scolopendria, Pisonia grandis and the endemic Santalum insulare var. hendersonense (Santalaceae). In this rugged landscape some of the fissures are up to 1.5 m deep and may contain the endemic Peperomia hendersonensis (Piperaceae) and ferns such as Nephrolepis hirsutala.

References

Florence, J., Waldren, S. & Chepstow-Lusty, A. J. 1995. The flora of the Pitcairn Islands: a review. Biological Journal of the Linnaean Society, 56: 79-119.

Fosberg, F. R. 1984. Phytogeographic comparison of Polynesia and Micronesia. In: Biogeography of the Tropical Pacific (Proceedings of a Symposium). Eds. F. J. Radovsky, P. H. Raven and H. Sohmer. Bishop Museum Special Publication No. 72.

Fosberg, F. R. & Sachet, M. H. 1975. Polynesian Plant Studies 1-5. Smithsonian Contribution to Botany, 21: 1-25.

Fosberg, F. R. & Sachet, M. H. 1981. Polynesian Plant Studies 1-5. Smithsonian Contribution to Botany, 47: 1-38.

Kingston, N. & Waldren, S. 2005. A conservation appraisal of the rare and endemic vascular plants of Pitcairn Island. Biodiversity and Conservation, 14: 781-800.

Mueller-Dombois, D. & Fosberg, F. R. 1998. Vegetation of the Tropical Pacific Islands. Springer.

Sohmer, S. H. 1990. Elements of Pacific phytodiversity. In: The Plant Diversity of Malesia. Proceedings of the Flora Malesiana Symposium commemorating Professor Dr. C. G. G. J. van Steenis Leiden, August 1989. Eds. P. Baas, K. Kalkman and R. Geesink. Kluwer Academic Publishers.

Waldren, S., Florence, J. & Chepstow-Lusty, A. J. 1995a. Rare and endemic vascular plants of the Pitcairn Islands, south-central Pacific Ocean: A conservation appraisal. Biological Conservation, 74: 83-98.

Waldren, S., Florence, J. & Chepstow-Lusty, A. J. 1995b. A comparison of the vegetation communities from the islands of the Pitcairn Group. Biological Journal of the Linnaean Society, 56: 121-144.

Wester, L. 1985. Checklist of vascular plants of the Northern Line Islands. Atoll Research Bulletin, 287: 1-38.

Wester, L., Juvik, J. O. & Holthus, P. 1992. Vegetation history of Washington Island (Teraina), northern Line Islands. Atoll Research Bulletin, 358: 1-50.