Recent Topics Posters
Marazzi, Brigitte .
The legumes Cassia, Chamaecrista and Senna in the Flora of North America
Cassia s.str., Chamaecrista and Senna were formerly known as Cassia s.l., one of the largest genera in Leguminosae, with ca. 700 species of trees, shrubs, herbs or lianas distributed worldwide. These species have long been studied and cultivated for their medicinal properties, showy inflorescences, and unusual floral morphological features associated with buzz pollination by pollen collecting bees. Recent molecular phylogenetic studies support the sister relationship between Cassia and Senna, but not the monophyly of the subtribe Cassiinae, which currently comprises the three genera. Chamaecrista and Senna still represent the two largest genera among caesalpinioid legumes, and the United States appears to represent the northern limit of their distribution. Up to six of 25-30 Cassia spp., 11 of ca. 350 Chamaecrista spp., and 31 of ca. 350 Senna spp. may occur in North America (NA; i.e., continental land North of Mexico). This tentative assessment is part of an ongoing taxonomic study for the Flora of North America Project, aimed at providing descriptions and identification tools, and other information (distribution outside NA, uses, etc.) for the species of these genera. Cassia is known in NA only from cultivated and introduced specimens. In contrast, almost all Chamaecrista and Senna species are native, including some endemics. The latter are widespread throughout the central and southern States from the east to the west coast (one or two species may extend into Canada, but this has yet to be verified). They have colonized various warmer habitats in NA ranging from the subtropics (Florida) to deserts (e.g., Sonoran and Mojave deserts). A number of species from each genus are presented.
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1 - University of Arizona, Ecology and Evolutionary Biology, Tucson, AZ, 85721, USA
Presentation Type: Recent Topics Poster
Location: Event Tent/Cliff Lodge
Date: Monday, July 27th, 2009
Time: 5:30 PM