The tribe Thomsonieae (Araceae) comprise two genera of palaeotropical herbs: Amorphophallus with approximately 200 species and Pseudodracontium with seven species. A phylogenetic study of the Thomsonieae is presented. Nucleotide sequences of the chloroplast gene matK and the trnL intron were analyzed for 46 Amorphophallus species, two Pseudodracontium species and six outgroups using maximum parsimony. The two data sets were analyzed separately and in combination. Amorphophallus can be divided into five major well-supported clades, which provide new hypotheses on infrageneric relationships. The branches connecting these clades, however, are poorly supported. Results are compared with previous morphology-based divisions of Amorphophallus. Remarkable results from this study are the monophyly of the African Amorphophallus species and the nesting of Pseudodracontium within Amorphophallus, making Amorphophallus in the traditional sense paraphyletic to Pseudodracontium.

Communicating Editor: Gregory M. Plunkett