Twenty-five genera having sterile inflorescence branches were recognized as the bristle clade within the x ¼ 9 Paniceae (Panicoideae). Within the bristle clade, taxonomic circumscription of Cenchrus (20–25 species), Pennisetum (80–140) and the monotypic Odontelytrum is still unclear. Several criteria have been applied to characterize Cenchrus and Pennisetum, but none of these has proved satisfactory as the diagnostic characters, such as fusion of bristles in the inflorescences, show continuous variation. Keywords: Pennisetum, Cenchrus, Odontelytrum, Poaceae, phylogenetic analyses, ndhF, trnL-trnF, kn1, apomixis.