Phylogeny in Artemisia (Asteraceae, Anthemideae) inferred from nuclear ribosomal DNA (ITS) sequences

The internal transcribed spacers (ITS-1 and ITS-2) of nuclear ribosomal DNA were sequenced for 33 populations of 31 species of Artemisia. The sequence data support the monophyly of the genus in its classical, broad sense, including Seriphidium and Oligosporus. Five main clades are defined, corresponding largely to the four main groups traditionally recognised in the genus: "Artemisia" (s.str.), "Absinthium", "Dracunculus", and "Seriphidium", plus the American "Tridentatae" segregated from the latter, except that "Artemisia", scattered over four different clades, is in need of a redefinition and restriction to the A. vulgaris clade. ITS data also support the hypothesis that the "Tridentatae" and "Seriphidium" are independent groups, and help differentiate the species in the A. herbaalba complex.