Volcano-Bonin Coastal Beaches
The beaches here are mainly colonized by widespread maritime species with Ipomoea pes-caprae usually the dominant fore dune species. Further inland the grass Cynodon dactylon and the coastal shrubs Scaevola sericea and Vitex rotundifolia dominate the dunes. The few endemic dune species here include the deciduous tree Erythrina boninensis (Fabaceae) and the dune grass Ischaemum ischaemoides (Poaceae).
Volcano-Bonin Coastal rocks and sea cliffs
The rocky maritime zone provides habitat for the endemic herbs Circium boninense (Asteraceae) and Sedum boninense (Grassulaceae), the endemic shrubs Lobelia boninensis (Campanulaceae) and Myoporum boninense (Myporaceae), and the small endemic tree Hedyotis mexicana (Rubiaceae). The coastal woodlands include the endemic shrub Fatsia oligocarpella (Araliaceae)
Volcano-Bonin Inland Forests
The remaining undisturbed forests supports many common endemic trees such as Cinnamomum pseudopedunculatum and Machilus kobu (Lauraceae), Ligustrum micranthum (Oleaceae), Pittosporum boninense (Pittorsporaceae), Boninia glabra, Evodia nishimurae (Rutaceae), Distylium lepidotum (Hamamelidaceae), Shima mertensii (Theaceae), Hibiscus glabra (Malvaceae), and three monocot trees Clinostigma savoryana, Livistonia boninensis (Arecaceae) and Pandanus boninensis (Pandanaceae). In fact, the screw pine (Pandanus boninensis) is possibly the most common tree in the BioProvince, but it was the endemic palm Clinostigma savoryana (cabbage palm) that made the island famous among whaling and other sea-faring men - the core of young plants provides a delicious food source. Other endemic trees such as Eurya boninensis (Theaceae), Morus boninensis (Moraceae), Stachyurus macrocarpus (Stachyuraceae), Symplocos boninensis (Symplocaceae) are much more rare. The endemic genus Boninia also includes the relatively common Boninia grisea, which forms large bushes rather than trees but can reach heights of up to 10 m. In sheltered gullies among palms and tree ferns grows the endemic Juniperus taxifolia (Cupressaceae), the only gymnosperm in the BioProvince. It grows to a height of about 15 m and is regarded as one of the most beautiful of the junipers. Of the 54 shrubby species found, at least 25 are endemic. In the forests these include Euonymus boninensis (Celastraceae) Gardenia jasmoides var. boninensis (Rubiaceae) and in the moss forests between 300-450m can be found Dendrocacalia crepidifolia (Asteraceae) representing the other endemic genus. Of the three tree ferns, two of them, Cyathea mertensiana and C. orugae (Cyatheaceae) are endemic. Other endemic ferns on the forest floor include Angiopteris boninensis (Angiopteridaceae), Marrattia boninensis (Marattiaceae), Schizaea boninensis (Schizaeaceae), Pteris boninensis (Pteridaceae), Bolbitis boninensis, Lomariopteris boninensis and Thelypteris boninensis (Aspidiaceae). There are at least twelve orchids all but one of them being endemic, and six of these, Calanthe hattorii, Corymborchis subdensa, Eulophia toyoshimae, Gastrodia boninensis, Goodyera boninensis, Platanthera boninensis and Zeuxine boninensis occur on the forest floor. Hanging from the trees are a variety of climbers including to at least 15 species. Endemics among these are Elaeagnus rotundata (Elaeagnaceae), Psycotria boninensis (Rubaceae) and Trachelospermum foetidum (Apocynaceae). The trees also support many epiphytic species including the endemic orchids Cirrhopatelum boninense and Luisia boninensis (Orchidaeceae), together with various endemic ferns such as Abrodictium boninense and Gonocormus bonincola (Hymenophyllaceae), Asplenium ikenoi (Aspleniaceae) and Pleopeltis boninensis (Polypodiaceae). The ancient but widespread Psilotum nudum is also a common epiphyte of these forests.
Volcano-Bonin Open Hill Tops
The windy hilltops and ridges support at least two types of vegetation. One is mainly composed of the endemic grass Miscanthus boninensis (Poaceae) and endemic sedge Carex hattoriana (Cyperaceae) - the other is typically dominated by the endemic shrub Osteomeles boninensis (Roseaceae) and sedges (Cyperaceae) of the genus Fimbristylis (such as the endemic F. longispica var. boninensis). Other endemics found in this zone include Boehmeria boninensis (Urticaceae), Portulaca boninensis (Portulacaceae), Clematis boninensis (Ranunculaceae), Distylium lepidotum (Hamamelidaceae), Wikstroemia pseudoretusa (Thymelaeaceae), Metrosideros boninensis (Myrtaceae), Vaccinium boninensis (Ericaceae) and Lycianthes boninensis (Solanaceae).
Other endemic species found in this BioProvince include Crepidiastrum ameristophyllum, C. linguafolium (Asteraceae) and Rhododendron boninense (Ericaceae).
Further information required.
References
Balgooy, Van. M. M. J. 1960. Preliminary plant geographical analysis of the Pacific. Blumea, 10: 385-430.
Hosokawa, T. 1934. Phytogeographical relationship between the Bonin and the Marianne islands laying stress upon the distribution of families, genera and species of their vernacular plants. Journal Soc.Tropical Agriculture, 6: 201-278.
Ito, M, Soejima, A. & Ono, M. 1998. Genetic diversity of the endemic plants of the Bonin (Ogasawara) Islands. In: Evolution and Speciation of Island Plants. Eds. T. S. Stuessy & M. Ono. Cambridge University Press.
Kawakubo, N. 1998. Evolution of cryptic dioecy in Callicarpa (Verbenaceae) on the Bonin Islands. In: Evolution and Speciation of Island Plants. Eds. T. S. Stuessy & M. Ono. Cambridge University Press.
Kobayashi, S. 1978. A list of vascular plants occuring in the Ogasawara (Bonin) Islands. Ogasawara Research, 1: 1-33.
Mueller-Dombois, D. & Fosberg, F. R. 1998. Vegetation of the Tropical Pacific Islands. Springer.
Nakai, T. 1930. The flora of the Bonin Islands. Bulletin of the Biogeographical Society of Japan, 1: 249-278.
Wilson. E. H. 1919. The Bonin Islands and their ligneous vegetation. Journal of the Arnold Arboretum, 1: 97-115.
Ono. M. 1998. Conervation of the endemic vascular plant species of the Bonin Islands. In: Evolution and Speciation of Island Plants. Eds. T. S. Stuessy & M. Ono. Cambridge University Press.
Tuyama, T. 1972. The status of the Bonin Islands flora in the Pacific. In: Floristics and Paleofloristics of Asia and eastern North America. Ed. A. Graham. Elsevier Publishing Company.