A series of phenetic and cladistic analyses (using ISS-flexible, NJTREE and HENNIG86) has been conducted on 166 generic descriptions of Chloridoideae, using 120 selected morphological and leaf anatomical characters. The results are emphatically not supportive of the traditional main division into the tribes Eragrosteae and Chlorideae, but instead indicate five quite different high level groups. By contrast, they afford strong support for the small tribes Pappophoreae, Orcuttieae, and Triodieae. They also highlight the special problems posed by polymorphic taxa (represented here by Eragrostis ) in planning and interpreting taxonomic and phylogenetic studies. Based on these findings a new classification model for the subfamily is proposed.