TORKE, BENJAMIN M.* and BARBARA A. SCHAAL. Washington University, Biology Department, Rebstock Hall, 1 Brookings Drive, St. Louis, Missouri, USA. - Preliminary phylogenetic, evolutionary, and monographic investigations in Swartzia (Leguminosae).
Swartzia (Leguminosae, Papilionoideae) is a large (ca. 180
species) and ecologically important genus of trees and shrubs found
throughout the New World tropics, particularly in lowland rainforests.
Previous authors have divided Swartzia into a number of
infrageneric groups based on morphology and have hypothesized about
the evolutionary polarity of morphological characters. Thorough
evaluation of previous classifications and evolutionary predictions
will require new knowledge of phylogenetic relationships within
Swartzia. This presentation summarizes previous infrageneric
classifications and hypotheses of character evolution in
Swartzia and discusses preliminary DNA sequence and
morphological data that have been collected by the authors. These data
will be used to construct a phylogeny reflecting the relationships
among the major species lineages of Swartzia. A well-resolved
phylogeny will serve as a basis for testing the monophyly of
Swartzia and the infrageneric groups of previous authors and
will provide an evolutionary context for investigating character
polarity and adaptive transitions. Flower and fruit morphology are
discussed and illustrated in relation to existing and planned studies
of pollination biology and dispersal ecology. Recently discovered
species and new monographic data on Swartzia series
Tounateae are used as examples to illustrate the need for
updated monographic and species delimitation work.
Key words: Fabaceae, Leguminosae, phylogeny, Swartzia, taxonomy