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Abstract Detail

Systematics Section/ASPT

O'Quinn, Robin [1], Stoughton, Thomas [2], Allen, Jessica [3].

Chasing Clade Resolution in Claytonia section Claytonia (Montiaceae).

Previous molecular phylogenetic analyses of Claytonia, a primarily temperate North American genus of succulent annuals and perennials, resolved three well-supported, monophyletic clades. Although relationships within two of the three clades were fairly well resolved (Claytonia sects. Limnia and Rhizomatosae), relationships within the third, Claytonia sect. Claytonia, were not. Lack of resolution in this clade of tuberous perennials impedes our better understanding of the biogeographic history and morphological evolution of lineages within it, and prevents effective taxonomic revision. We hypothesize that this lack of resolution is the result of a complex evolutionary history during the Pleistocene that includes multiple bouts of polyploidy and hybridization. As a preliminary step towards unraveling the processes driving diversification within and among lineages in Claytonia sect. Claytonia, we sought to 1) develop primary species hypotheses, 2) test the monophyly of known species complexes, and 3) revise the current taxonomy. In this study we significantly increase our taxon sampling to include the breadth of variation across the clade, with specific emphasis on known species complexes including C. megarhiza, C. lanceolata and C. umbellata. We assess relationships among lineages using a suite of chloroplast markers, with resolving utility across a range of evolutionary scales, and the internal transcribed spacer region (ITS). Preliminary results from analysis of ITS on an expanded taxon set suggests that none of the species complexes are monophyletic, and support the hypothesis that hybridization coupled with polyploidy is a significant contributing factor to the evolution of tuberous perennial Claytonia. Likewise, current taxonomy does not reflect evolutionary history for these historically well-supported groups. Instead, our analyses identify an intricate network of embedded species complexes suitable for further investigation including the C. “peirsonii” complex, a group of subalpine plants currently circumscribed within the enigmatic C. lanceolata complex from the mountains of western North America. Subtle variations in morphology, ecology, and geographic location will likely further identify unique lineages that can be recognized at the species level. Using this preliminary study as a backbone to inform further investigation in this system and others, we expect to contribute to a greater understanding of the evolution of promiscuity in Angiosperms.

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1 - Eastern Washington University, Biology 234-C Science Building, Cheney, WA, 99004-2440, USA
2 - Rancho Santa Ana Botanic Garden, Claremont Graduate University, 1500 North College Avenue, Claremont, CA, 91711, USA
3 - The New York Botanical Garden, Institute of Systematic Botany, Bronx, NY, 10458-5126, USA


Presentation Type: Oral Paper:Papers for Sections
Session: 4
Location: Magnolia/Riverside Hilton
Date: Monday, July 29th, 2013
Time: 9:15 AM
Number: 4004
Abstract ID:845
Candidate for Awards:None

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