Saunders, N. E. , Sipes, S.D. .
A Molecular Phylogeny of Abronia Juss. (Nyctaginaceae).
Abronia Juss. (Nyctaginaceae) is a small group of psammophiles and gypsophiles, endemic to North America, primarily west of the 100th meridian. Composed of approximately 20 species, the group is characterized by small population size, adaptation to a highly specific and uncommon habitat, and tolerance of environmental extremes. Species are found in maritime, montane, and desert habitats. The genus is thought to have only recently radiated into the North American deserts, and many taxa are thought to be actively speciating. Modern treatments rely on highly variable morphological characters, resulting in an unstable taxonomy. Compounding the problem, many Abronia hybridize in sympatry producing a number of species complexes—-a few of these hybrids may be common enough to have achieved species or subspecies status. We undertook a phylogenetic analysis of the genus to see if the addition of molecular characters could resolve some of the more vexing species complexes and offer a more stable taxonomy. We sampled 90 populations representing 17 recognized Abronia and four outgroup species from within the Nyctaginaceae. Our preliminary analysis indicates that there are two well supported maritime clades, with Abronia latifolia distinct from the other maritime species with which it grows in sympatry. The third clade includes both desert and montane species, in which our data weakly supports a cold desert and a hot desert grouping. There appears to be no morphological or molecular support for the separation of Abronia villosa and Abronia umbellata, which have been considered a species complex in need of further study. However, we identified three other species complexes in need of further investigation.
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1 - Southern Illinois University Carbondale, Department of Plant Biology, 1125 Lincoln Dr., Mail Code 6509, Carbondale, IL, 62901-6509, USA
2 - Southern Illinois University Carbondale, Plant Biology and Center for Ecology, 1125 Lincoln Dr., mail code 6509, Carbondale, Il, 62901, USA
Presentation Type: Oral Paper:Papers for Sections
Location: 554/Convention Center
Date: Wednesday, August 4th, 2010
Time: 2:00 PM