Tropical Biology Section
Schlessman, Mark A. , Vary, Laura B. , Lowry II, Porter P. , Munzinger, Jérôme .
Sexual Systems of the New Caledonian Flora.
The flora of the southwest Pacific Island of New Caledonia is remarkable for its richness (> 3200 species), high level of endemism (± 80%), and distinctive composition, which includes descendants of both Gondwanan relicts and more recent long-distance colonizers, as well as many species adapted to ultramafic soils. While several studies have focused on particular taxonomic groups and vegetation types, the floral biology of New Caledonian plants is poorly known. We used the literature, herbarium specimens, and field observations to determine the sexual systems of 97.8% of the described native species of angiosperms. Of those, 79% are sexually monomorphic (i.e. cosexual; 61.1% hermaphroditic, 13.4% monoecious, 4.1% andromonoecious, 0.7% gynomonoecious), and about 21% are sexually dimorphic (dioecious 20.2%, androdioecious 0.4%, gynodioecious 0.2%). The frequencies of monoecy, andromonoecy, and dioecy are higher than those for angiosperms as a whole. Dioecy and (to a lesser extent) monoecy are over-represented among species of dense evergreen forests, and monoecy is also over-represented in wetlands. Andromonoecy is over-represented among halophytes and in wetlands and disturbed habitats. Hermaphroditism is noticeably under-represented in dense evergreen forest and over-represented in disturbed habitats, as well as in the characteristic maquis vegetation of ultramafic soils. The high incidences of dioecy and monoecy are due, at least in part, to associations of both systems with woodiness and tropical forest habitats. The high frequency of andromonecy may simply be an artifact of overlooking the system in previous global estimates.
1 - Vassar College, Department of Biology, Vassar College Box 187, 124 Raymond Ave., Poughkeepsie, New York, 112604-0187, U.S.A.
2 - Institute de Recherche pour le Dévelopement, B.P. A5, 98848, Nouméa Cedex, , Nouvelle-Calé:donie
3 - Missouri Botanical Garden, PO Box 299, St. Louis, Missouri, 63166-0299, USA
Presentation Type: Poster
Location: Special Event Center (Cliff Lodge)
Date: Tuesday, August 3rd, 2004
Time: 12:30 PM