Recent Topics Posters
Guilliams, Matt , Lee, Daniel , Baldwin, Bruce .
The Use of Continuous Quantitative Data to Delimit Species in the Boraginaceae - A Case Study in Plagiobothrys.
Plagiobothrys (Boraginaceae) is a predominantly New World genus of approximately 85 annual and perennial minimum-rank taxa. Nutlet morphology has received considerable attention from taxonomists and has historically informed species circumscriptions. Recent molecular work suggests that North American species of Plagiobothrys section Allocarya possessing relatively large nutlets with stout prickles (e.g., P.acanthocarpus, P. austiniae, P. greenei, P. hystriculus) form a monophyletic group. This clade is widely distributed in the California Floristic Province in vernal pool ecosystems and other ephemerally inundated settings. One extremely rare member of this group, P. hystriculus (CNPS list 1B.1, formerly CNPS list 1A), was thought to be extinct until populations were rediscovered by Schafer and colleagues in 2005. Here we present a pilot study demonstrating the use of continuous quantitative measurements of the nutlets of target Boraginaceae in a morphometric analysis for the purpose of species circumscription. The study focuses on the prickly-nutleted members of Plagiobothrys section Allocarya, with an emphasis on evaluating the distinctiveness of P. hystriculus, as well as comparing recent collections with historical collections upon which this putative taxon is based. Univariate analyses (e.g., ANOVA) show many statistically significant differences between the morphologically similar P. greenei and P. hystriculus for a number of continuous quantitative morphological features. Multivariate analyses show strong clustering by taxon, regardless of whether taxon identification is considered a priori. Importantly, recent collections are assignable to P.hystriculus in our analyses, confirming the rediscovery of this latter taxon. This study is the first attempt to use a large morphometric dataset for taxon circumscription in Plagiobothrys. Based upon the demonstrated utility of this approach, these data will be expanded for use in phylogenetic analyses of extant and fossil Boraginaceae.
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1 - University Of California, Berkeley, University And Jepson Herbaria, 1001 Valley Life Sciences Building #2465, Berkeley, CA, 94720, USA
2 - University of California, Berkeley, Integrative Biology, 1001 Valley Life Sciences Building #2465, Berkeley, CA, 94720-2465, United States
3 - University Of California Berkeley, JEPSON HERB & DEPT INTEGR BIOL, 1001 Valley Life Sciences Building, MC 2465, Berkeley, CA, 94720-2465, USA
Presentation Type: Recent Topics Poster
Location: Battelle South/Convention Center
Date: Monday, July 9th, 2012
Time: 5:30 PM