BAILEY†, C. DONOVAN*, ROBERT A. PRICE‡, AND JEFF J. DOYLE†. †L.H. Bailey Hortorium, Cornell University, 462 Mann Library, Ithaca, NY 14853. ‡Department of Botany, University of Georgia, 2502 Miller Plant Science Bldg, Athens, GA 30602-7271. - MONOPHYLY OF THE HALIMOLOBINE BRASSICACEAE.
Halimolobos, Mancoa, Pennellia, and Sphaerocardamum are
New World Brassicaceae genera with their greatest species diversity in
Mexico. The familial classification for these genera has been
controversial. Our higher level studies, using DNA sequence data from
ndhF and trnL intron, suggested that some species of
these genera represent a monophyletic group. The goal of the present
study was to test the monophyly of the group and their relationships
relative to one another with additional species samples and data
sources. Data were generated from three independent loci (chloroplast
trnL intron - trnL/F spacer, nrDNA ITS, and
pistillata intron 1) and morphology for 26 of their currently
recognized 48 species. The difficulties associated with incorporating
these data into total evidence analyses are discussed and our strategy
is presented. Separate and total evidence analyses identify a
monophyletic core group of Halimolobos, Mancoa, Pennellia, and
Sphaerocardamum species that is closely related to members of
the Arabidopsoid lineage. In addition, the results suggest that
Pennellia and Sphaerocardamum are monophyletic but that
Halimolobos and Mancoa are polyphyletic. Silique
characteristic appear to be highly plastic within the lineage while
characteristics of the corolla, seeds, and trichomes are relatively
stable.
Key words: Cruciferae, Halimolobos, Mancoa, Pennellia, Phylogeny, Sphaerocardamum