Halpin, Kate , Fishbein, Mark .
A chloroplast phylogeny of Agavaceae subfamily Chlorogaloideae and the placement of Hesperocallis with a focus on species delimitation in Hastingsia.
Serpentine soils throughout the Klamath-Siskiyou region of southwestern Oregon and northern California form a patchy, fragmented landscape. These isolated outcrops contain toxic concentrations of heavy metals, making them unsuitable for most plant species. An incredible diversity of species inhabits serpentine, but these are often rare, endangered and narrowly endemic. Hastingsia (Agavaceae) is a genus of two to four rare species that are mainly restricted to serpentine. The closest relatives of this genus are thought to be Schoenolirion, Chlorogalum, and Camassia, together comprising subfamily Chlorogaloideae. Other than a close relationship between Camassia and Chlorogalum, however, phylogenetic relationships of these genera have gone largely unstudied. Furthermore, there is evidence that a fifth genus, Hesperocallis, is closely related to Chlorogaloideae, but its placement has not been tested explicitly with phylogenetic analyses. Within Hastingsia, recognition of two recently described species has been widely disputed due to the difficulty in consistently observing diagnostic differences. To address the taxonomic status of the newly described H. serpenticola and H. atropurpurea and determine relationships among the genera of Chlorogaloideae, we obtained DNA sequences from 44 specimens sampled across the ranges of all species of Hastingsia and one to three specimens from each species of Schoenolirion, Chlorogalum, Camassia, and Hesperocallis. Four non-coding loci from the chloroplast genome, the rpl16 intron, and the trnS-trnfM, trnD-trnT, and ndhF-rpl32 spacers were sequenced. Phylogenetic analyses in parsimony, likelihood, and Bayesian frameworks were used to test the monophyly of all species of Hastingsia and estimate relationships within subfamily Chlorogaloideae. Preliminary results suggest Hesperocallis is closely related to Chlorogaloideae, but its placement is unresolved relative to Schoenolirion, and that no species of Hastingsia is monophyletic, with some relationships corresponding to better to geography than taxonomy.
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1 - Oklahoma State University, Department of Botany, 104 Life Sciences East, Stillwater, OK, 74078, USA
Presentation Type: Oral Paper:Papers for Sections
Location: 555A/Convention Center
Date: Monday, August 2nd, 2010
Time: 9:15 AM