ibclogo XVI International Botanical Congess


Abstract Number: 2890
Poster No. = 819


EVOLUTION AND PHYLOGENETIC RELATIONSHIPS WITHIN ERIOGONOIDEAE (POLYGONACEAE).


Rashmi Pant and J. Mark. Porter Porter, Rancho Santa Ana Botnic Garden1500-N college Ave,


Eriogonoideae, a subfamily in Polygonaceae, consists of 320 species classified in seventeen genera. Historical classifications differ in relative inclusiveness of two large genera, Eriogonum and Chorizanthe. This is reflected in the large number of satellite genera currently recognized. Phylogenetic estimates from sequences of internal transcribed spacer (ITS) of the nuclear ribosomal region, and chloroplast trnL intron and trnL-trnF intergenic spacer region show that Eriogonum, Chorizanthe, and Oxytheca as currently circumscribed are not monophyletic groups. These data point to reticulate evolution and/or the use of homoplastic characters in current classifications. The presence of awns, a basis for recognition of Chorizanthe, Oxytheca and various monotypic genera has based upon character reconstruction been gained at least four times, with as many losses, thus suggesting involucral awns are a very homoplastic character.


HTML-Version made 7. July 1999 by Kurt Stüber