ROALSON, ERIC H.1*, LAURENCE E. SKOG2, JOHN K. BOGGAN2, and ELIZABETH A. ZIMMER2,3. 1School of Biological Sciences, Washington State University, Pullman, WA 99164-4236; 2Department of Systematic Biology - Botany, MRC-166, NMNH, Smithsonian Institution, Washington, DC 20560; 3Laboratories of Analytical Biology, National Museum of Natural History, Smithsonian Institution, Suitland, Maryland 20746. - Generic boundaries in the Gloxinieae (Gesneriaceae): tracking diversification and convergence in floral form with nuclear, chloroplast, and morphological cladistic data sets.
The Gloxinieae (Gesneriaceae) tribe includes 22 genera and
approximately 290 species, as currently circumscribed. Recent
molecular phylogenetic studies have suggested that some members of the
tribe (the genera Sinningia, Paliavana, and
Vanhouttea) are not closely related to the rest of the tribe.
Additionally, other species (i.e., Gloxinia sarmentiana) appear
to not belong to the Gloxinieae. The Gloxinieae have traditionally
been troublesome, both in circumscription of generic boundaries and
membership in tribal classifications. This is in part due to extreme
variation in floral form in this group. In order to address questions
of generic boundaries, tribal classification, the evolution of floral
form, and biogeographic distribution patterns, we have analyzed
morphological cladistic, nuclear ribosomal ITS sequence, and
chloroplast DNA trnL-F spacer sequence data sets with maximum
parsimony and maximum likelihood. These data sets support a number of
findings. These include recognition of the genus Gloxinia, as
currently circumscribed, as polyphyletic, that the genus
Capanea is derived from within Kohleria, and that the
tribe may have originated in Central America and the Caribbean, with
later dispersal to South America.
Key words: classification, floral evolution, Gesneriaceae, Gloxinieae, molecular phylogenetics, morphological cladistics