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Abstract Detail

Systematics Section/ASPT


Systematic analyses of the sessile trilliums, Trillium subgenus Phyllantherum.

The sessile trilliums are recognized within the distinctive genus Trillium as subgenus Phyllantherum.  The defining morphological character of the subgenus is the lack of a floral peduncle, so that the flower appears to be sessile and attached immediately above the whorl of three bracts (or leaves) that characterizes the genus.  The plants are perennial herbs and usually have notably mottled bracts.  Although the genus as a whole exhibits the classical trimodal geographic distribution in eastern Asia, western North America, and eastern North America, subgenus Phyllantherum is restricted to the latter two regions.  With about 25 species currently recognized, they constitute about half of the species-level diversity of the genus.  New data from complete sequencing of the plastid genome revealed a major inversion in the ndhC-rbcL region as well as pseudogenization of the accD gene as possible apomorphies for Trillium and its congeners of tribe Paridae.  Comparative results suggested plastid spacer regions suitable for analysis of interspecific relationships and also candidates for phylogeographic studies.  Results of  phylogenetic analyses based on nuclear ITS and plastid spacer regions showed subgenus Phyllantherum to be monophyletic, with early diverging clades from southeastern North America.  Species from western North America were hardly differentiated from one another, and embedded among the eastern North American lineages, suggesting a relatively recent movement of the subgenus from east to west in North America. The relatively high level of variability revealed by survey studies suggests that additional species level diversity in eastern North America may remain to be described.

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1 - University Of Tennessee, Department Of Ecology & Evolutionary Biology, 569 Dabney Hall, KNOXVILLE, TN, 37996-1610, USA
2 - University Of Tennessee, Ecology & Evolutionary Biology, 569 Dabney Hall, Knoxville, TN, 37996, USA
3 - Abraham Baldwin Agricultural College, ABAC 15, 2802 Moore Hwy, Tifton, GA, 31793-2601, USA


Presentation Type: Oral Paper:Papers for Sections
Session: 13
Location: Pines South/Boise Centre
Date: Monday, July 28th, 2014
Time: 1:45 PM
Number: 13002
Abstract ID:770
Candidate for Awards:None

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