Systematics Section / ASPT
Smith, James F. , Stillman, Amy J. , Larson, Steven , Culumber, C. Mae , Robertson, Ian , Novak, Stephen J. .
A phylogenetic analysis of Lepidium papilliferum and L. davisii (Brassicaceae) reveal the relations of these rare endemic species.
Previously phylogenetic analyses of Lepidium included only a few accessions of L. montanum and L. fremontii to represent the western North American species. Two additional species endemic to southwest Idaho have posed both taxonomic and conservation questions regarding their species status. Lepidium papilliferum was originally described as a variety of L. montanum, and is found in small scattered populations in southwest Idaho. The plant is restricted to specific edaphic conditions known as slick spots where high clay content creates conditions amenable to L. papilliferum, but to few other species. Like L. papilliferum, L. davisii has specific edaphic requirements and is found in playas, areas similar to slick spots, but larger and with deeper soils. Previous phylogenetic studies have shown that American species of Lepidium are apparently allopolyploids with one genome derived from an African clade and the other from an Asian/European clade. In this study we have expanded previous analyses to include both L. papilliferum and L. davisii along with several accessions of L. montanum along with published sequences of ITS, cpDNA and PISTILLATA first intron. Our results agree with previous studies in that this group of species has one genome derived from within an African clade and another from within an Asian/European clade. The western North American species form a monophyletic group with L. davisii sister to the remainder of the clade. Within this clade L. papilliferum and L fremontii are each monophyletic and sister to each other, but are imbedded within a paraphyletic L. montanum. These data suggest that greater sampling among populations and subspecies of L. montanum and other western North American species of Lepidiumwill be required before less inclusive clades that may best be recognized as distinct species are fully revealed.
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1 - Boise State University, Department of Biology, 1910 University Drive, Boise, Idaho, 83725-1515, USA
2 - Boise State University, Biology, 1910 University Drive, Boise, ID, 83725, USA
3 - Utah State University, Usda-Ars, Forage And Range Research Laboratory, Logan, Utah, 84322-6300, USA
4 - Utah State University, USDA-ARS Forage and Range Research Laboratory, Logan, UT, 84341
5 - Department of Biology, Boise State University, 1910 University Drive, Boise, Idaho, 83725-1515, USA
PISTILLATA first intron
Presentation Type: Oral Paper:Papers for Sections
Location: Boulevard C/Hilton
Date: Wednesday, July 11th, 2007
Time: 11:30 AM