Molecular phylogeny of the portulacaceous cohort

The central focus of this research is the use of chloroplast ndhF sequence data to produce a phylogeny of the Portulacaceae, including an evaluation of the relationships of this family to the Basellaceae, Cactaceae, and Didiereaceae. This cohort was divided into two major clades, both including genera of the Portulacaceae; the Cactaceae were derived from the first, and the Basellaceae and Didiereaceae from the second. Within the latter, a largely Western American assemblage of genera, some formerly identified as basal taxa, was found to be monophyletic. This phylogeny indicated that all recent infrafamilial classifications of the Portulacaceae were flawed by the recognition of non-monophyletic tribes, and that generic limits remain an issue, particularly in Talinum, Calandrinia, and Cistanthe. Rapidly evolving chloroplast sequences were used to evaluate two monophyletic lineages within the cohort: the Didiereaceae and the tribe Anacampseroteae. The sister group of the Didiereaceae was Calyptrotheca (Portulacaceae); present taxonomic understanding of the family was supported. Talinopsis was identified as the basal lineage of the Anacampseroteae, and it was determined that Talinaria was derived from within Anacampseros and that Anacampseros Subg. Tuberosae was polyphyletic