A Phylogeny of <i>Piptochaetium</i> (Poaceae: Pooideae: Stipeae) and Related Genera Based on a Combined Analysis including <i>trnL-F,</i> <i>rpl16</i>, and Morphology

Abstract

Abstract The tribe Stipeae occurs in temperate and warm temperate grasslands of Eurasia, Australia, and America. Although generic circumscription within the tribe has recently undergone significant changes, the American genus Piptochaetium has been clearly defined by morphological and anatomical characters. It includes 36 species and 2 varieties, most of them widely distributed in temperate grasslands of South America. Phylogenetic analyses were conducted in Piptochaetium and allied genera of the Stipeae, in order to test the monophyly of the genus, re-examine infrageneric taxa, and analyze relationships among species of this genus and allied genera of Stipeae. Two chloroplast molecular markers, trnL-F and rpl16, as well as morphology were used. Topology between morphological and molecular data mainly differs in the relationships of Piptochaetium with Anatherostipa and Piptatherum. Molecular and combined analyses yielded two major clades in the tribe: the x  =  11 Clade with Piptochaetium, Aciachne, Anath...