Systematics Section / ASPT
Chan, Raymund , Funk, Vicki A. .
Is the tribe Arctoteae (Compositae: Cichorioideae) monophyletic? More data, more taxa, some answers, even more questions.
RECENT molecular (ITS, ndhF, trnL-F) and morphological studies in the tribe Arctoteae have provided a basic structure for its phylogeny but left several questions unanswered. Additional data (matK) and additional taxa have been added to the data matrix and the questions have been re-examined. Like the previous work this study shows that the two sub-tribes Goreteriinae and Arctotinae are strongly monophyletic from both molecular and morphological data. Also, Haplocarpha, Hirpicium, and Berkheya remain paraphyletic. Some of the problem taxa have been placed: Platycarpha is definitely not in the Arctoteae and is sister to the Vernonieae-Liabeae clade but on a long branch. Heterolepis is sister to the subtribe Arctotinae but we have not yet found morphological support for this. The Eremothamneae (Eremothamnus + Hoplophyllum) stands alone as the sister taxon to the Arctoteae-Liabeae-Vernonieae clade and so its subtribal status should be maintained. The relationship among the two subtribes and the Platycarpha-Liabeae-Vernonieae clade is unresolved and so we cannot determine if the tribe Arctoteae is monophyletic. Analysis using a variety of outgroups has produced some interesting results including some support for Platycarpha being placed separate from the Liabeae-Vernonieae clade. Additional taxa from the Vernonieae and Liabeae need to be added to the analysis to stabilize the base of the tree.
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1 - National Museum of Natural History, Smithsonian Institution, Department of Botany, MRC-166, P.O. Box 37012, Washington, DC, 20013-7012, USA
Presentation Type: Oral Paper:Papers for Sections
Date: Wednesday, August 2nd, 2006
Time: 2:00 PM