Systematics Section / ASPT
Douglas, Norman .
A Molecular Phylogeny of the Four O.
The family Nyctaginaceae comprises approximately 30 genera distributed primarily in the tropical and subtropical New World. Previous phylogenetic work has placed the family in the Caryophyllales, though its sister lineage is uncertain. In this study we sampled ITS, rpl16, rps16, and ndhF from representatives for 50 species in 25 genera, plus eight genera from Phytolaccaceae, Sarcobataceae, Aizoaceae, Molluginaceae, and Stegnospermataceae. The tribal classification presented by Bittrich & Kühn is accurate with the exception of tribe Nyctagineae, which is highly artificial, as are three of its subtribes. We recovered a well-supported clade of 11 genera of xeric-adapted annual and perennial herbs principally from the deserts of North America, whereas the genera from the tropics of South America are not a monophyletic group. The Neotropical genera Neea and Guapira are not found to be distinct. Within the clade of desert herbs, it is clear that obligate gypsophily and the annual habit have each evolved at least three times. Characters previously thought to be taxonomically important such as the presence of an involucre and pollen morphology are homoplasious.
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1 - Duke University, Department of Biology, 139 Biological Sciences Building, PO Box 90338, Durham, North Carolina, 27708, USA
Presentation Type: Oral Paper
Date: Monday, August 15th, 2005
Time: 1:30 PM