Phylogeny of North AmericanFestuca(Poaceae) and related genera using chloroplast DNA restriction site variation

摘要

Phylogenetic relationships in the genusFestuca, as expressed in recent classification systems, were tested using chloroplast DNA restriction endonuclease site variation data. Species native or introduced to North America were used as exemplars for taxa related toFestucathat have been recognized variously as genera, subgenera, and (or) sections. Cladistic analysis of 67 shared chloroplast DNA restriction site mutations indicated thatFestucaand some related taxa, as circumscribed in morphologically based classifications, appear to be non-monophyletic. Cluster analysis of 108 polymorphic sites was largely congruent with the results of the cladistic analysis. Two main evolutionary lines were indicated. One contained the majority of the genusFestucaexemplars, including the subgeneraDrymanthele,Subulatae,Subuliflorae,Obtusae, andFestuca, as well asVulpia,Argillochloa, and subg.Leucopoasect.Breviaristatae. The other lineage included subgenusSchedonorus, subg.Leucopoasect.Leucopoa, and the genusLolium. Analyses supported the recognition of two genera in each lineage:VulpiaandFestucain one, andLeucopoasensu stricto (including only sect.Leucopoa) andLolium(includingFestucasubg.Schedonorus) in the other. The recognition of the monotypic generic segregateArgillochloa(=F.dasyclada) was not supported by the analyses.Key words:Festuca,Leucopoa,Lolium,Vulpia, phylogeny, chloroplast DNA.