title: A phylogeny and classification of the Muhlenbergiinae (Poaceae: Chloridoideae: Cynodonteae) based on plastid and nuclear DNA sequences.
abstract: OBJECTIVE
  To understand the origins of C(4) grasslands, we must have a better interpretation of plant traits via phylogenetic reconstruction. Muhlenbergiinae, the largest subtribe of C(4) grasses in Mexico and the southwestern United States (with 176 species), is taxonomically poorly understood. •
  
  
  METHODS
  We conducted a phylogenetic analysis of 47 genera and 174 species using six plastid regions (ndhA intron, ndhF, rps16-trnK, rps16 intron, rps3, and rpl32-trnL) and the nuclear ITS 1 and 2 (ribosomal internal transcribed spacer) regions to infer evolutionary relationships and revise the classification. •
  
  
  RESULTS
  In our analyses, Muhlenbergia (ca. 153 species) is paraphyletic, with nine genera (Aegopogon, Bealia, Blepharoneuron, Chaboissaea, Lycurus, Muhlenbergia, Pereilema, Redfieldia, Schaffnerella, and Schedonnardus) found nested within. We recognized the following five well-supported monophyletic lineages within Muhlenbergia: subg. Muhlenbergia, with species that have phosphoenolpyruvate carboxykinase-like leaf anatomy and long, scaly rhizomes; subg. Trichochloa with long-lived species that are relatively tall (up to 3 m); subg. Clomena with 3-nerved upper glumes; sect. Pseudosporobolus species with narrow panicles and plumbeous spikelets; and sect. Bealia species with lemmas with hairy margins and midveins. •
  
  
  CONCLUSIONS
  We propose expanding the circumscription of Muhlenbergia to include the other nine genera in this subtribe and make the following new combinations: Muhlenbergia subg. Bealia, M. diandra, M. geminiflora, M. paniculata, M. phleoides, M. subg. Pseudosporobolus (also lectotipified), M. solisii, M. tricholepis. We also propose several new names: M. ammophila, M. columbi, M. plumosa. Our phylograms suggest that Muhlenbergia originated in North America because the sister (Sohnsia filifolia and Scleropogoninae) is composed of predominantly North American species.
authors: Smithsonian Institution, Department of Botany MRC-166, National Museum of Natural History, Washington, D.C. 20013-7012 USA.
authors: Paul M
authors: PM
authors: Peterson
authors: Konstantin
authors: K
authors: Romaschenko
authors: Gabriel
authors: G
authors: Johnson