title: Vigna (Leguminosae) sensu lato: the names and identities of the American segregate genera.
abstract: OBJECTIVE
  The legume genus Vigna and close relatives have highly elaborated floral morphologies that involve the coiling, bending, and intricate connection of flower parts. Banners, levers, platforms, and pumps have evolved that attract pollinators and then manipulate their movement. Given this three-dimensional floral complexity, the taxonomy of Vigna and relatives has been confounded by the study of mostly two-dimensional museum specimens. A molecular phylogenetic analysis was undertaken in the effort to resolve long-standing taxonomic questions centered on floral morphology.
  
  
  METHODS
  The phylogenetic analysis included cpDNA trnK and nuclear ribosomal ITS/5.8S (ITS) sequence variation. The American species were comprehensively sampled and outgroups included Old World relatives.
  
  
  RESULTS
  The trnK and ITS data analyses concurred in resolving six well-supported clades of American Vigna that are most closely related to other American genera: Dolichopsis, Macroptilium, Mysanthus, Oryxis, Oxyrhynchus, Phaseolus, Ramirezella, and Strophostyles. These 14 American clades ranked here as genera are resolved as sister to a clade comprising the mainly Old World species of Vigna.
  
  
  CONCLUSIONS
  American Vigna clades were reassigned to the genera Ancistrotropis, Cochliasanthus, Condylostylis, Leptospron, Sigmoidotropis, and the newly described Helicotropis. Vigna sensu stricto in the Americas now includes relatively few and mostly pantropical species. Elaborate floral asymmetries are readily used to apomorphically diagnose nearly all of the American genera. The age estimates of the extant diversification of the American and its Old World sister clade are approximately coeval at ca. 6-7 million yr, which belies much greater floral variation in the Americas.
authors: Universidad Nacional Autónoma de México, Instituto de Biología, Departamento de Botánica, México, Distrito Federal, Mexico. adelgado@ibiologia.unam.mx
authors: Alfonso
authors: A
authors: Delgado-Salinas
authors: Mats
authors: M
authors: Thulin
authors: Rémy
authors: R
authors: Pasquet
authors: Norm
authors: N
authors: Weeden
authors: Matt
authors: M
authors: Lavin
mesh_terms: D000569:Americas; D001483:Base Sequence; D018742:DNA, Chloroplast / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000235:genetics; D019143:Evolution, Molecular; D007887:Fabaceae / Q000033:anatomy & histology / Q000145:classification* / Q000235:genetics; D035264:Flowers / Q000033:anatomy & histology; D005843:Geography; D010802:Phylogeny; D013223:Statistics as Topic; D009626:Terminology as Topic
chemical_list: D018742:DNA, Chloroplast; D021903:DNA, Ribosomal Spacer