GROSE, SUSAN O.* and RICHARD G. OLMSTEAD. Department of Botany, Box 355325, University of Washington, Seattle, WA 98195-5325. - Phylogenetic analysis of Crescentieae and Tabebuia s.l. (Bignoniaceae).
The Bignoniaceae tribe Crescentieae consists of 33 species in three
genera. It belongs to a group of Mesoamerican plants putatively
adapted for dispersal by the Pleistocene megafauna. Alwyn Gentry
hypothesized that the common ancestor of this tribe was similar to the
neotropical genus Tabebuia . Previous molecular studies have
confirmed this relationship, and have shown that while Bignoniaceae
are monophyletic, one tribe, the Tecomeae, is paraphyletic. One of
these Tecomeae clades consists of Tabebuia s.l. and the three
genera of Crescentieae. This supports a monophyletic Crescentieae but
suggests that Tabebuia is paraphyletic unless it is expanded
to include Crescentieae. The purpose of this research is to further
resolve this relationship. Sequences of the chloroplast genes
ndhF, trnL/trnF and the nuclear ribosomal ITS/ETS
are being obtained to resolve the relationships within and between
Tabebuia and the Crescentieae.
Key words: Bignoniaceae, Crescentieae, phylogeny, Tabebuia