SIMMONS, SARAH L.* and JOSE L. PANERO. School of Biological Sciences, Section of Integrative Biology, University of Texas, Austin, TX 78712. - Phylogeny and biogeography of Staphyleaceae (DC.) Lindl.
One of the most interesting facets of angiosperm biogeography is the
disjunct distribution of closely related plant groups. When seeking
plausible explanations for the origins of biogeographical patterns,
analyses of the phylogenetic relationships of disjunct taxa are
critical. It is particularly important to seek a phylogenetic
framework when morphological data is sparse or ambiguous, as is the
case for the family Staphyleaceae. The family, (composed of three
genera, Staphylea, Euscaphis, and Turpinia,
totaling 50-60 species) exhibits two intriguing biogeographical
patterns. Staphylea is distributed in temperate North America,
Europe and Asia, while Turpinia is disjunct between the tropics
of the new world (Mexico to South America) and the old world (central
Asia to Papua New Guinea). The genus Euscaphis is monotypic and
occurs in eastern Asia. The three genera of Staphyleaceae are
delimited primarily on the basis of fruit type, with few other
characters to distinguish them. This raises additional questions: is
the presence of fleshy fruits (Turpinia) the result of a
relictual distribution of a wider ranging fleshy-fruited taxon, or are
the fruits a misinterpreted result of convergence? To answer questions
regarding biogeographical patterns, generic circumscription,
phylogenetic relationships within the genera, and character
convergence we initiated a study using sequence data from one nuclear
(ITS 1 and 2) and two chloroplast (matK-psbA and
trnT-trnL) regions. Results from comparative studies
based on sequence data revealed that traditional generic groupings are
polyphyletic and a re-evaluation of the generic limits is necessary.
Data gathered to date and its implications for the interpretation of
the biogeographic history of Staphyleaceae will be discussed.
Key words: biogeography, Euscaphis, ITS, Staphylea, Staphyleaceae, Turpinia