XVI International Botanical Congess

With as many as 2000 species, the tribe Euphorbieae is the largest tribe of the Euphorbiaceae, and all but eight species belong to subtribe Euphorbiinae. Euphorbia is by far the largest genus, and the other eight to ten genera of Euphorbiinae have all previously been treated within Euphorbia. In this investigation, relationships within Euphorbiinae are investigated using two molecular data sets: the noncoding internal transcribed spacer region (ITS) of nuclear ribosomal DNA and the coding chloroplast region ndhF. Results from maximum likelihood and maximum parsimony analyses of these data are compared and contrasted with the traditional classification of Euphorbiinae. It is supported that all of the smaller segregate genera of Euphorbia are monophyletic. However, these are nested within a highly paraphyletic Euphorbia.