Systematics/Phytogeography / Taxonomie/ Section
Halpin, Kate , Fishbein, Mark .
Species delimitation in Hastingsia (Agavaceae): insights from chloroplast DNA.
Hastingsia (Agavaceae) is a genus of unique and rare plants. It consists of 2-4 species, which are restricted to the Klamath-Siskiyou region of Oregon and California, with one species ranging to the northernmost Sierra Nevada. The genus is thought to be most closely related to Schoenolirion, Chlorogalum, and Camassia (Camas Lily). Three of the four species of Hastingsia recognized in the most recent revision (in Flora North America) are restricted to isolated outcrops of serpentine rock, whereas H. alba is found both on and off this substrate. Serpentine soils have been of great interest to ecologists and evolutionary biologists because they contain toxic levels of metals, giving rise to high levels of edaphic endemism. Also, the patchy nature of exposed serpentine rock creates many small and isolated populations, leading in many cases to extreme rarity of species. Until recently, only two species of Hastingsia were recognized: H. bracteosa and H. alba. In Flora North America, H. atropurpurea is segregated from H. bracteosa and H. serpenticola is segregated from H. alba. Recognition of these segregates has been questioned, but never tested with phylogenetic or popuation genetic analyses. Resolution of these taxonomic issues is essential for the conservation of these serpentine endemics. To address the taxonomic status of H. serpenticola, we collected specimens from throughout the ranges of H. serpenticola and H. alba. Two non-coding loci from the chloroplast genome, the rpl16 intron and trnD-trnT spacer, were sequenced. Phylogenetic analyses were used to test the reciprocal monophyly of H. serpenticola and H. alba. In future work, the population genetic structure of these species will be evaluated and the recognition of H. serpenticola will be reevaluated.
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1 - Portland State University, Biology, Po Box 751, Portland, Oregon, 97207, USA
2 - Portland State University, Biology Department, Po Box 751, Portland, Oregon, 97207-0751, USA
Presentation Type: Poster:Posters for Sections
Location: Ball Room & Party Room/SUB
Date: Monday, July 28th, 2008
Time: 12:30 PM