Systematics Section / ASPT
Riggins, Chance , Seigler, David S. .
Phylogenetic relationships and biogeography of Artemisia (Asteraceae, Anthemideae) based on nuclear rDNA ITS sequence data.
A phylogenetic study of Artemisia s. l. and allied genera in the tribe Anthemideae has been conducted using nuclear ribosomal ITS data and expanded taxon sampling. The generic and infrageneric boundaries of Artemisia were reexamined in greater detail compared to earlier studies by augmenting previously published ITS sequence data with newly acquired sequences obtained from the majority of species found in North America and the Russian Far East. Also, intraspecific sequence diversity was investigated in several Artemisia species with disjunct distributions in the region formerly connecting both continents (i.e., Beringia), as well as in species with populations found in Greenland, the Queen Charlotte Islands, and other islands in the Bering Sea region, Canadian Arctic Archipelago, and the Kuril Archipelago. Results from the ITS analysis show that the genus Artemisia is not monophyletic as currently circumscribed, but rather paraphyletic by the exclusion of several small segregate genera from Asia (i.e., Crossostephium, Filifolium, Mausolea, Neopallasia, and Turaniphytum) and the North American genus Sphaeromeria. Section Seriphidium of the genus Artemisia, which is sometimes recognized as a distinct genus, is clearly embedded within a large clade of Artemisia species. Additional clades correspond to groups of taxa traditionally placed in other sections of the genus Artemisia, namely sect. Absinthium, sect. Dracunculus (with the inclusion of Mausolea and Turaniphytum), and sect. Tridentatae. Members of sect. Artemisia are scattered throughout the tree, although two subclades are recognized. One consists of the North American members of the A. ludoviciana complex which is sister to a second clade composed of Eurasian species related to A. vulgaris. Intraspecific diversity of the ITS sequence region is low or nonexistent in all insular and/or continental disjunct taxa examined.
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1 - University of Illinois Urbana, Department of Plant Biology, 239 Morrill Hall, 505 South Goodwin Avenue, Urbana, Illinois, 61801-3707, USA
2 - University of Illinois Urbana, Department of Plant Biology, 265 Morrill Hall, 505 South Goodwin Avenue, Urbana, Illinois, 61801-3707, USA
Presentation Type: Poster:Posters for Sections
Location: Auditorium/Bell Memorial Union
Date: Tuesday, August 1st, 2006
Time: 12:30 PM