The chloroplast trnL-F region was sequenced for 20 species of Velloziaceae sensu stricto plus Acanthochlamys and representative species of Cyclanthus (Cyclanthaceae) and Pandanus (Pandanaceae) as outgroups. Phylogenetic analysis of the trnL intron and trnL-F intergenic spacer placed the Asian Acanthochlamys as a distant but well-supported sister-group to a monophyletic Velloziaceae sensu stricto. Within the Velloziaceae, the subfamily Barbacenioideae sensu Menezes is well supported as monophyletic, in agreement with chromosomal and morphological data, while the subfamily Vellozioideae may be paraphyletic. At least two of the currently recognized genera within the Barbacenioideae (Aylthonia and Barbacenia) appear to be paraphyletic or polyphyletic as currently delimited, while the genus Burlemarxia appears to have arisen recently within a subgroup of Barbacenia. These results appear most consistent with the inclusion of all or almost all of the taxa of the Barbacenioideae within a broadly delimited genus Barbacenia. Within the subfamily Vellozioideae, trnL-F data are consistent with the segregation of the South American Nanuza from Vellozia as a distinct genus, while the South American species sometimes placed in Xerophyta are not distinct from Vellozia.

Communicating Editor: John V. Freudenstein