A molecular phylogeny and classification of the Cteniinae, Farragininae, Gouiniinae, Gymnopogoninae, Perotidinae, and Trichoneurinae (Poaceae: Chloridoideae: Cynodonteae)

The classification of twenty Cynodonteae genera ( Bewsia, Craspedorhachis, Ctenium, Dignathia, Farrago, Gouinia, Gymnopogon, Latipes, Leptocarydion, Leptothrium, Lophacme, Lopholepis, Mosdenia, Perotis, Schenckochloa, Toliara, Trichoneura, Trigonochloa, Triplasis, Vaseyochloa ) has been poorly understood. The goals of this study were to reconstruct the evolutionary history of the tribe Cynodonteae, emphasizing these twenty genera using molecular data with increased species sampling. A phylogenetic analysis was conducted on 159 samples, of which 94 species (140 individuals) were in the Cynodonteae, using four plastid ( rpl32‐trnL spacer, ndhA intron, rps16‐trnK spacer, rps16 intron) and nuclear ITS 1&2 (ribosomal internal transcribed spacer regions) sequences to infer evolutionary relationships and revise the classification. Strong support was found for six lineages. Craspedorhachis, Ctenium, Dignathia, Gymnopogon, Trichoneura , and Triplasis appear monophyletic; Leptothrium is paraphyletic with Latipes inermis embedded within; Perotis is paraphyletic with Lopholepis and Toliara embedded within; and Gouinia is monophyletic with the resurrection of Schenckochloa . The molecular results support the recognition of six subtribes; five (Cteniinae, Farragininae, Gymnopogoninae, Perotidinae, Trichoneurinae) are newly described. A new genus, Tridentopsis , is described; five new combinations, Leptothrium inerme, Perotis arenacea, Perotis ornithocephala, Tridentopsis eragrostoides , and Tridentopsis mutica are made; and Holboellia ornithocephala is lectotypified.