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United States Department of Agriculture

Agricultural Research Service

Research Project: IMPROVED PLANT GENETIC RESOURCES FOR PASTURES AND RANGELANDS IN THE TEMPERATE SEMIARID REGIONS OF THE WESTERN U.S. Title: Phylogenetic Relationships Among Lepidium Papilliferum

Authors
item Smith, James - BOISE STATE UNIVERSITY
item Stillman, Amy - BOISE STATE UNIVERSITY
item Larson, Steven
item Culumber, C - UTAH STATE UNIVERSITY
item Robertson, Ian - BOISE STATE UNIVERSITY
item Novak, Stephen - BOISE STATE UNIVERSITY

Submitted to: The Journal of the Torrey Botanical Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 5, 2009
Publication Date: June 3, 2009
Citation: Smith, J.F., Stillman, A.J., Larson, S.R., Culumber, C.M., Robertson, I.C., Novak, S.J. 2009. Phylogenetic Relationships Among Lepidium Papilliferum. The Journal of the Torrey Botanical Society. 136:149-163.

Interpretive Summary: Previous phylogenetic analyses of Lepidium included only a few accessions of L. montanum, L. flavum, and L. fremontii to represent 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 allopolyploids with one genome derived from an African clade and the other from an Eurasian clade. In this study, we have expanded previous phylogenetic analyses to include L. papilliferum, L. davisii, and several accessions of L. montanum. The western North American species form a distinct group with L. davisii sister to the remainder of the group. Within this group, L. papilliferum and L. fremontii are each distinct and sister to each other, but are subgroup of L. montanum.

Technical Abstract: Previous phylogenetic analyses of Lepidium included only a few acessions of L. montanum, L. flavum, and L. fremontii to represent western North Amrican 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. Tha 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 phylogenic studies have shown that American species of Lepidium are allopolyploids with one genome derived from an African clade and the other from an Eurasian clade. In this study, we have expanded previous analyses to include L. papilliferum, L. davisii, and several accessions of L. montanum along with published sequences of ITS, cpDNA and PISTILLATA first intron. 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 Lepidium will be required before less inclusive clades that may best be recognized as distinct species are fully revealed.

Last Modified: 10/25/2014
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