Systematic studies in Paniceae (Poaceae): Homopholis and Whalleya gen. et sp nov.

The taxonomy of Homopholis C. E. Hubb. is revised, and a new genus Whalleya K. E. Wills & J. J. Bruhl is described. Relationships among the known spec ies of Homopholis (H. belsonii C. E. Hubb., H. proluta F. Muell., and a put ative species, H. sp. nov.), and the relationships between Homopholis and o ther genera within the Paniceae were investigated. Morphological and anatom ical data for Homopholis and selected species of Digitaria and Panicum were analysed phenetically and cladistically. The value and contribution of cha racters to the findings were assessed. In the phenetic analyses, three dist inct clusters of species were formed. The first cluster included Digitaria coenicola (F. Muell.) Hughes, D. divaricatissima (R. Br.) Hughes and D. pap posa (R. Br.) P. Beauv.; the second, Panicum effusum R. Br., P. queenslandi cum Domin var. queenslandicum and P. simile Domin; and the third, H. sp. no v., H. proluta, H. belsonii and P. subxerophilum Domin. Specimens of H. bel sonii noticeably separated from the other three species. For the cladistic analyses, species of Entolasia and Thyridolepis were used as outgroup taxa. One most parsimonious tree was produced. Homopholis belsonii was well supp orted as the most basal member of the ingroup. The three species of Digitar ia formed a well-supported clade. Panicum effusum, P. queenslandicum var. q ueenslandicum and P. simile formed a well-supported clade, and were the sis ter group to Entolasia marginata (R. Br.) Hughes and E. stricta (R. Br.) Hu ghes. Panicum subxerophilum was in a clade (= Whalleya) with H. sp. nov. an d H. proluta, with P. subxerophilum and H. proluta as sister species.