A CLADISTIC-ANALYSIS OF PARKIA (LEGUMINOSAE, MIMOSOIDEAE)

A cladistic analysis of the tropical mimosoid genus Parkia was underta ken to examine relationships among the 31 species and to test the mono phyly of the three recognized sections. The implications of the cladog ram to the evolution of bat-pollination and biogeography were also exp lored. The analysis, based on 52 morphological characters, resulted in 408 most parsimonious trees. A consensus tree supports the monophyly of sections Parkia and Platyparkia, but section Sphaeroparkia is parap hyletic. The latter section is distinguished by a capitulum of all fer tile flowers, a plesiomorphic attribute in this analysis. Characters s upporting the monophyly of section Platyparkia include an inflorescenc e with distal nectar flowers having exserted styles, and fruits with s eeds in two rows. Section Parkia is characterized by having sterile ba sal flowers with nectar flowers just above them, and calyx lobes inclu ded in bud. Bat-pollination was mapped onto one of the most parsimonio us cladograms to examine the evolution of pollination syndromes within the genus. Our phylogeny is consistent with a single origin of bat-po llination and indicates that entomophilous species of Parkia are basal rather than secondarily derived. Sections Platyparkia and Parkia are separate lineages within the bat-pollinated clade and have independent ly developed capitulum types adapted to chiropterophily. Characters th at are associated with chiropterophily include specialized nectar-prod ucing flowers and basifixed anthers. Several characters, including pre sence of a staminodial fringe, a nectar ring, and pollen with verrucat e sculpturing on the exine, probably represent increasing specializati on for bat-pollination. The cladogram supports a South American origin for Parkia but is not consistent with a Gondwanan vicariance event as is usually hypothesized to explain its amphi-Atlantic distribution.