TL;DR: Phylogenetic analyses of plastid and nuclear ribosomal DNA show that Eremopoa species are nested within the genus Poa, in a clade that is accepted as Poasubg.Pseudopoa, synonymy for and a key to the taxa.
Abstract: Eremopoa is a small genus of annual grasses distributed from Egypt to western China. Phylogenetic analyses of plastid and nuclear ribosomal DNA show that Eremopoa species, together with the monotypic genus Lindbergella and a single species of Poa (P.speluncarum), are nested within the genus Poa, in a clade that we accept as Poasubg.Pseudopoa. Here we accept seven species, four subspecies and four varieties in Poasubg.Pseudopoa. Five new combinations are made: Poaattalica, P.diaphora var. alpina, P.diaphora var. songarica, P.nephelochloides and P.persicasubsp.multiradiata; P.millii is proposed as a replacement name for E.capillaris; and Poa sections Lindbergella and Speluncarae are proposed. We provide a diagnosis for Poasubg.Pseudopoa, synonymy for and a key to the taxa. Eight lectotypes are designated: Eragrostisbarbeyi Post, Eremopoanephelochloides Roshev., Glyceriataurica Steud., Nephelochloatripolitana Boiss. & Blanche, Poacilicensis Hance, Poaparadoxa Kar. & Kir., Poapersicavar.alpina Boiss and Poapersicasubsp.cypria Sam. Eremopoamedica is re-identified as a species of Puccinellia.
TL;DR: A phylogenetic study of Poa based on trnT-trnF chloroplast DNA sequence data is presented focusing on basal relationships, major clades, generic boundaries, and placement of putatively closely related genera.
Abstract: Poa, the largest genus of grasses (Poaceae) with over 500 species, occurs throughout temperate and boreal regions in both hemispheres. A phylogenetic study of Poa based on trnT-trnF chloroplast DNA sequence data is presented focusing on basal relationships, major clades, generic boundaries, and placement of putatively closely related genera. Results support the monophyly of the main lineage of Poa if subgen. Andinae is excluded and Anthochloa, Austrofestuca, Dissanthelium (at least in part), and Eremopoa are included. The main Poa clade and subgen. Andinae resolve within a strongly supported Poinae-Alopecurinae-Miliinae clade (PAM). The subdivision of Poa into five major clades, proposed based on chloroplast restriction site data, is supported by sequence data. The basal-most clade (ArcSyl) comprises Poa subgen. Arctopoa and subgen. Poa sect. Sylvestres, two groups having disparate morphology, but similar cpDNA. The next-diverging clade (BAPO), comprising sects. Bolbophorum, Alpinae, Parodiochloa, and Ochlopoa, is strongly supported and characterized by highly divergent cpDNA. The majority of Poa species and sections form a strongly supported clade comprising major clades SPOSTA. PoM, and HAMBADD. Newly reported in this study is Eremopoa as a distinct lineage positioned between this higher Poa clade and BAPO. A revised infrageneric classification of Poa comprising five subgenera is proposed. Two new subgeneric divisions of Poa are proposed: subgen. Stenopoa for the SPOSTA clade and supersect. Homalopoa for the HAMBADD clade. The monotypic genus Anthochloa is reduced to Poa sect. Anthochloa, and its one species recognized as Poa lepidula.