PHYLOGENY AND CLASSIFICATION OF VOYRIA (SAPROPHYTIC GENTIANACEAE)

A cladistic analysis of the saprophytic genus Voyria Aubl. (Gentianace ae) was performed to evaluate infrageneric classification, character e volution, and biogeography. A matrix of 19 species of Voyria and 39 mo rphological characters yielded three most-parsimonious trees, one of w hich was identical to their strict consensus. The major division withi n Voyria based on character support is also the rooting point suggeste d by a larger cladistic analysis of gentians. We have chosen to treat these distinct clades as two new subgenera, Voyria subgen. Voyria Aubl . and Voyria subgen. Leiphaimos (Schltdl. Br Cham.) V. A. Albert & L. Struwe. stat. nov. Concerning character evolution, Voyria subgen. Voyr ia (5 spp.) is the most similar to other Gentianaceae. The saprophytic condition is more advanced in Voyria subgen. Leiphaimos (14 spp.), in which stomates and a continuous vascular cylinder are lacking. Within subgen. Leiphaimos, trends toward extreme vascular reduction and wind -mediated seed dispersal are evident. The extensive character evolutio n observed within Voyria as a whole may correlate with relaxation of a utotrophic structural constraints. Optimization of an area of distribu tion character on the cladograms obtained suggests that Guayana (and t herefore northern South America) may rep; resent the most ancestral ar ea for extant Voyria.