SAMUEL, ROSABELLE1*, TOD F. STUESSY1, and CARLOS M. BAEZA2. 1Department of Higher Plant Systematics and Evolution, Institute of Botany, University of Vienna, Rennweg 14, Vienna, Austria; 2Departamento de Botanica, Universidad de Concepcion, Concepcion, Chile. - Molecular Phylogeny of Hypochaeris (Asteraceae) and Relationships to Other Genera of Hypochaeridinae.
Nuclear internal transcribed spacer regions (ITS) and the chloroplast
trnL intron and trnL/trnF intergenic spacer and matK sequences were
used to assess relationships among European and South American species
of Hypochaeris. The ITS tree shows high resolution compared to that of
the maternally inherited trnL and matK. Monophyly of south American
Hypochaeris is strongly supported by both ITS and the joint matrix of
ITS, trnL and matK data. The European species lie basal to the South
American taxa. This, plus small molecular divergence among South
American species, suggests that they evolved from a single
introduction from a European progenitor similar to H. maculata (or
possibly H. cretensis or H. oligocephala), and not from H. radicata or
H. robertia as suggested previously. Hypochaeris is also revealed to
be paraphyletic in relation to generic relatives. ITS data indicate
that H. robertia is closer to Leontodon helveticus and L. autumnalis,
which brings its placement within Hypochaeris into serious question.
Species of Leontodon form two clades based on molecular data, each
also supported by chromosome numbers and morphology. Both nuclear and
chloroplast markers suggest that Leontodon, Picris and Helminthotheca
are very closely related genera and all need taxonomic re-evaluation.
Key words: Asteraceae, DNA, evolution, Hypochaeris, phylogeny, South America