URBATSCH, LOWELL E. Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803. - Phylogeny of the Rudbeckiinae (Heliantheae, Asteraceae) based on cpDNA restriction site data and ITS, ETS, and 5’, 3’ trnK sequence data.
Subtribe Rudbeckiinae is a small North American monophyletic lineage
of Heliantheae composed of approximately 35 species distributed among
the genera Dracopis, Ratibida, and Rudbeckia.
Four molecular data sets will be used individually and in combination
with one another for the purpose of phylogenetic reconstruction.
Chloroplast restriction site investigations provide strong support
for certain species groups in Rudbeckiinae, but relationships among
these clades are largely unresolved. ITS sequence data provide a
highly resolved phylogeny that, in general, support traditional
concepts for the group. The Ratibida clade has strong support,
and in most analyses it is sister to Rudbeckia.
Rudbeckia, is resolved as two sublineages corresponding to
traditional circumscriptions of subg. Macrocline and subg.
Rudbeckia. Dracopis, traditionally recognized as a
distinct genus, is sister to Rudbeckia subg. Macrocline.
Species relationships suggested by the two data sets are highly
congruent, but some exceptions are evident. Examining additional
sequence data from other nuclear and chloroplast markers seek
explanations for such discrepancies. Preliminary analysis of external
transcribed spacer (ETS) sequence data results in a phylogeny similar
to that generated from ITS sequences. Additional chloroplast data are
being sought from the 5’ and 3’ regions of the trnK intron. Efficacy
of combining the data sets to generate a phylogeny based on total
evidence is being examined.
Key words: Asteraceae, Dracopis, phylogeny, Ratibida, Rudbeckia, Rudbeckiinae