Abstract Detail

Systematics Section/ASPT

Alford, Mac [1], Cameron, Kree [2].

DNA Evidence for the Recognition of Several Species of Cudweeds (Gamochaeta, Asteraceae) in the Eastern United States.

Gamochaeta (Asteraceae) is a common genus of weedy plants in the eastern United States. Some have recognized as few as one species in this region, but others have recognized as many as eight species. Although the eastern North American representatives are morphologically variable, the variation could be environmental, allelic (intra-specific), representative of unique features for several species, or even indicative of unrecognized introductions to the flora. Here a genetic study was undertaken to assess whether the morphological variation as represented in putative species corresponds to genetic differences. A nuclear region of DNA, the internal transcribed spacer (ITS), and one plastid region, the intergenic spacer trnH-psbA, were sequenced, and haplotypes were compared among the morphological samples of the eight putative species. The results indicate that the putative species have unique genetic markers as well as morphological features. Given the sampling of U.S. species, the phylogeny also indicates that the cudweeds with bicolor leaves form a monophyletic group.

Broader Impacts:

1 - University of Southern Mississippi, Department of Biological Sciences, 118 COLLEGE DRIVE #5018, HATTIESBURG, MS, 39406-0001, USA
2 - University of Southern Mississippi, Department of Biological Sciences, 118 College Dr. #5018, Hattiesburg, MS, 39406-0001, USA

Keywords:
Gamochaeta
Asteraceae
Compositae
Gnaphalieae
species concept
species complex
cudweed.

Presentation Type: Oral Paper:Papers for Sections
Session: 35
Location: Versailles Ballroom/Riverside Hilton
Date: Tuesday, July 30th, 2013
Time: 4:45 PM
Number: 35013
Abstract ID:326
Candidate for Awards:None