A PHYLOGENETIC ANALYSIS OF THE AUREOID SENECIO (ASTERACEAE) COMPLEX BASED ON ITS SEQUENCE DATA

The internal transcribed spacer region of the 18S-25S nuclear ribosoma l DNA repeat was sequenced from 28 populations of the aureoid Senecio complex as well as two populations from the Lugentes group and one fro m the Tephroseroid group. Divergence levels for populations within the aureoid complex are very low (0.0 to 4.1%). Phylogenetic trees genera ted from the sequence data provide no support for the recognition of A urei, Tomentosi and Lobati subgroups within the aureoid complex. With two Lugentes and one Tephroseroid species as outgroups, Senecio glabel lus is the sister group of the rest of the aureoids. The high level of divergence between the aureoids and the three outgroup species indica tes that the Lugentes and the Tephroseroids may not be closely related to the aureoids.