Daniel, Thomas F. .
Acanthaceae of the United States and Canada: Taxonomy and Distribution.
Preparation of a floristic treatment of Acanthaceae for the Flora of North America project (FNA) has resulted in the first comprehensive account of the family for the region in 125 years. The family is represented in the United States and Canada by 19 genera (13 native) and 77 species (60 native). Although no genera are restricted to the region covered by FNA, 20 species (33% of native species) are endemic to the United States, and at least six others are nearly endemic there. The largest genera in the United States and Canada are Justicia (14 native spp., five endemic spp.) and Ruellia (13 native spp., 10 endemic spp.). Because of its tropical nature Acanthaceae are best represented in those regions of the United States with subtropical climates (Arizona, Florida, and Texas). The number of species quickly diminishes northward from the southern tier of states, with only one species (Justicia americana) reaching southern Canada. This pattern is especially pronounced in the western United States where species are found only in the southern, arid portions of California, Arizona, and New Mexico. Most occurrences of Acanthaceae in the FNA region are in the moist/humid southeastern United States and in the arid/semiarid southwestern United States. Texas occupies the boundary between these regions, is enriched by taxa from each, and has more species of Acanthaceae (47, 42 native) than any other state or province in the FNA region. The two states with the greatest species richness, Texas and Florida (35 species, 19 native), occupy the southernmost portions of the FNA region. Most poorly resolved taxonomic problems among Acanthaceae in the FNA region are to be found within their borders and involve species and infraspecific taxa of Justicia and Ruellia. Taxonomic and nomenclatural changes proposed for North American Acanthaceae demonstrate the usefulness of studying these plants in a broader geographic context than heretofore undertaken.
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1 - California Academy of Sciences, Botany, 55 Music Concourse Drive, Golden Gate Park, San Francisco, CA, 94118, USA
Presentation Type: Poster:Posters for Sections
Location: Battelle South/Convention Center
Date: Monday, July 9th, 2012
Time: 5:30 PM