XVI International Botanical Congess

Previous systematic studies of the Portulacaceae based on comparativemorphology, chromosome numbers, and analyses of nuclear sequence data have produced competing classifications. The current systematic view of the portulacaceous cohort of the Order Caryophyllales includes the families Basellaceae, Didiereaceae and Cactaceae as derived from within the Portulacaceae, thus enforcing its distinction as a paraphyletic entity. We have examined molecular variation in the plastid encoded gene ndhF in order to assess its potential in resolving the inter- and infrafamilial relationships within the portulacaceous cohort. Our molecular systematicstudies of this group of families, in general, support the current conceptwith minor modification. A phylogeny derived from the ndhF data is presented in the context of the previously published studies of the cohort.Implications for familial and tribal classification will be addressed briefly.