Systematics/Phytogeography / Taxonomie/ Section
Naczi, Robert F. C. , Knapp, Wesley M. .
Systematics of the Rhynchospora plumosa group (Cyperaceae).
Within Rhynchospora section Plumosae, a clade of 5–7 species endemic to warm-temperate and tropical areas in the Western Hemisphere, the R. plumosa group is the largest and most problematic. Circumscriptions of the taxa are controversial, with some authors recognizing as few as 2 and others as many as 5 species in the group. The group has never been revised, and its monophyly is uncertain. Morphologic features that characterize the group include spikelets numerous and sessile in fascicles, perianth bristles plumose, and achene bodies suborbicular in cross-section. Plants of the R. plumosa group grow in sandy, nutrient-poor soils in savannas, wet pinelands, and scrub. Members of the group occur in the southeastern U.S.A., Central America, and the Greater Antilles. Geographic distributions of the taxa exhibit both narrow endemism and wide disjunctions. Our goals are to determine if the group is monophyletic, determine the number of taxa within the group, determine the ranks of the taxa, identify diagnostic characters of the taxa, and reconstruct the phylogeny for the group (if monophyletic) or for the largest portion of the group that is monophyletic. Macromorphology, micromorphology, and anatomy are all yielding important data for this revision.
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1 - Delaware State University, Claude E. Phillips Herbarium, Department Agriculture & Natural Resources, 1200 N Dupont Highway, Dover, Delaware, 19901-2277, USA
2 - Maryland Department of Natural Resources, Wildlife and Heritage Service, P.O. Box 68, 909 Wye Mills Rd., Wye Mills, MD, 21679, U.S.A.
Rhynchospora section Plumosae.
Presentation Type: Oral Paper:Papers for Sections
Date: Tuesday, July 29th, 2008
Time: 10:15 AM