ROALSON, ERIC H.1*, LARRY E. SKOG2, and ELIZABETH A. ZIMMER1. 1Laboratory of Molecular Systematics, NMNH, MRC-534, Smithsonian Institution, Washington, DC 20560; 2Department of Systematic Biology - Botany, MRC-166, NMNH, Smithsonian Institution, Washington, DC 20560. - Floral diversification and phylogenetic relationships in Achimenes (Gesneriaceae).
Achimenes (Gloxinieae; Gesneriaceae) includes approximately 25
species of perennial herbs distributed from Mexico south through
Central America to northern South America. Six sections are
recognized: Achimenes, Dicyrta, Guthnickia,
Locheria, Plectopoma, and Scheeria. These
sections have traditionally been defined based on flower
type/pollination syndrome. Flowers can be salverform, tubular, or
funnelform in shape and red, yellow, purple, pink, or white in color.
Additionally, some species have a distinct floral spur while others
have no enlargement of the floral tube base. Phylogenetic
relationships in the genus were explored using sequence data from the
nrDNA internal transcribed spacer (ITS) and cpDNA trnL-F and
trnE-T spacer regions. Results suggest that the large sections
Achimenes and Dicyrta are polyphyletic. Some
relationships supported by the molecular data correlate well with
vegetative morphological characteristics. Patterns of floral evolution
will be discussed.
Key words: Achimenes, floral evolution, Gesneriaceae, Gloxinieae, molecular phylogenetics