title: Molecular phylogenetics of Echinopsis (Cactaceae): Polyphyly at all levels and convergent evolution of pollination modes and growth forms.
abstract: OBJECTIVE
  In its current circumscription, Echinopsis with 100-150 species is one of the largest and morphologically most diverse genera of Cactaceae. This diversity and an absence of correlated characters have resulted in numerous attempts to subdivide Echinopsis into more homogeneous subgroups. To infer natural species groups in this alliance, we here provide a plastid phylogeny and use it to infer changes in growth form, pollination mode, and ploidy level.
  
  
  METHODS
  We sequenced 3800 nucleotides of chloroplast DNA from 162 plants representing 144 species and subspecies. The sample includes the type species of all genera close to, or included in, Echinopsis as well as a dense sample of other genera of the Trichocereeae and further outgroups. New and published chromosome counts were compiled and traced on the phylogeny, as were pollination modes and growth habits.
  
  
  RESULTS
  A maximum likelihood phylogeny confirms that Echinopsis s.l. is not monophyletic nor are any of the previously recognized genera that have more than one species. Pollination mode and, to a lesser extent, growth habit are evolutionarily labile, and diploidy is the rule in Echinopsis s.l., with the few polyploids clustered in just a few clades.
  
  
  CONCLUSIONS
  The use of evolutionary labile floral traits and growth habit has led to nonnatural classifications. Taxonomic realignments are required, but further study of less evolutionary labile traits suitable for circumscribing genera are needed. Surprisingly, polyploidy seems infrequent in the Echinopsis alliance and hybridization may thus be of minor relevance in the evolution of this clade.
authors.affiliation: Systematic Botany and Mycology, University of Munich, Germany. boris.schlumpberger@hannoverstadt.de
authors.forename: Boris O
authors.initials: BO
authors.lastname: Schlumpberger
authors.forename: Susanne S
authors.initials: SS
authors.lastname: Renner
mesh_terms: D001483:Base Sequence; D029421:Cactaceae / Q000145:classification* / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D032461:Chromosomes, Plant / Q000235:genetics; D016000:Cluster Analysis; D018742:DNA, Chloroplast / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics; D019143:Evolution, Molecular; D035264:Flowers / Q000145:classification / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D014644:Genetic Variation; D008969:Molecular Sequence Data; D010641:Phenotype; D010802:Phylogeny; D011003:Ploidies; D054817:Pollination; D017422:Sequence Analysis, DNA
chemical_list: D018742:DNA, Chloroplast; D018744:DNA, Plant