THE CIRCUMSCRIPTION OF HOFFMANNSEGGIA (FABACEAE, CAESALPINIOIDEAE, CAESALPINIEAE) AND ITS ALLIES USING MORPHOLOGICAL AND CPDNA RESTRICTION SITE DATA

The controversial issue of the circumscription of Hoffmannseggia and i ts relationship to Caesalpinia was examined using morphological charac ters and chloroplast:DNA restriction site data from 32 species. The 53 morphological characters used included several not previously explore d, but together they still failed to give unequivocal resolution of th e taxa examined. However, morphological characters did provide some ev idence for a Hoffmannseggia clade, but different from that traditional ly circumscribed. The cpDNA restriction site analysis using 16 enzymes yielded 233 informative characters that provided strong evidence for a Hoffmannseggia clade. Both data sets supported the circumscription o f a distinct ''Pomaria'' clade consisting in part of species tradition ally placed within Hoffmannseggia. Nevertheless, both Hoffmannseggia a nd Pomaria and their allies fall within a larger clade of species trad itionally considered to belong to Caesalpinia broadly defined. Because Caesalpinia itself appears to be polyphyletic, we advocate here maint aining Hoffmannseggia with the expectation that species of Caesalpinia s. 1. will ultimately be reapportioned to a number of smaller, monoph yletic genera.