Systematics Section / ASPT
Garrison, Laura , Patterson, Robert , Spicer, Greg S. .
Molecular Phylogeny of Phacelia subgenus Phacelia (Boraginaceae).
PHACELIA (Boraginaceae) is a large genus (approximately 200 species), well represented in California and other western states. It has been divided into three subgenera (Cosmanthus, Howellanthus, and Phacelia). Subgenus Phacelia has been further divided into sections. Section Phacelia is the largest and least studied of these, and has been informally divided into eight species groups. The Crenulatae group consists primarily of desert annuals. Its range extends from southern California east to Texas and north through Utah into Idaho and Wyoming. There are members native to each of the four major desert systems (Great Basin, Sonoran, Mojave, and Chihuahan). Species in this group are distinguished from other members of sect. Phacelia by their quadriovulate fruits and by seed surface characters. As part of an ongoing study of Phacelia systematics, we are investigating the relationship of species in the Crenulatae group to other species in subgenus Phacelia. The Crenulatae group has been considered daunting because of its size and the existence of gradations in morphological characters. The group is taxonomically labile and has been unevenly collected. There has not yet been a comprehensive phylogenetic study of sect. Phacelia. We have sampled 37 taxa from 75 collections from throughout the geographic range of the section, and have combined these sequences with previously published Phacelia sequences for analysis. The resulting data set comprises 88 taxa. A molecular phylogeny based on ITS sequence data reflects the complexity of the group, yet provides insight on species relationships and species identity in this complex. In addition, the ITS phylogeny enables assessment of the evolutionary history of morphological characters traditionally used to distinguish these species.
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1 - San Francisco State University, Department of Biology, 1600 Holloway Avenue, San Francisco, California, 94132
Presentation Type: Oral Paper:Papers for Sections
Date: Wednesday, August 2nd, 2006
Time: 9:00 AM