Phylogeny of Poaceae inferred from matK sequences

Complete sequences of the plastid gene matK were determined for 62 species of Poaceae from 60 genera. 26 tribes. and nine subfamilies to infer phylogenetic relationships. Restio tetraphyllus (Restionaceae) and Joinvillea ascendens (Joinvilleaceae) were used ai outgroups. Cladistic analysis using PAUP yielded 39 most parsimonious trees with several well-supported major linenges. The strict consensus tree shows Streptochaeta and Anomochloa forming the two most basal lineages in grasses, followed by Pharus being sister to the remaining species. The other grasses divide into three clades: (1) subfamily Bambusoideae (excluding Brachyelytrum) plus Pooideae: (2) Oryzoideae: and (3) subfamilies Panicoideae, Arundinoideae. Centothecoideae, and Chloridoideae (termed PACC). Except For Arundinoideae, monophyly of each PACC subfamily is generally well supported: however, relationships among subfamilies are unresolved or weakly supported. Results obtained using matK sequences are largely consistent with other phylogenies based on molecular and structural data, particularly in that relationships among subfamilies remain unclear.