A morphometric approach in plumose and pappus-like awn South American stipoids

Within grasses, the tribe Stipeae is highly specialized by the presence of only one fruit per spikelet and characterized by the diversity on the ornamentation of the floret. Our aim was to analyze similarities based on multi and uni-variate analyses among species reflecting evolutionary trends in American Stipeae: Jarava species with plumose awns, and species of Pappostipa, all characterized by pappus-like awns. Ordination analyses (Principal coordinates analysis and Cluster analysis) were used to determinate major groupings, while significant differences among groups were tested by multivariate analysis of variance (MANOVA) and univariate analysis based on a generalized linear model (GLM). We delimited five groups. Small floret characterizes Jarava annua, J. media and J. plumosula, although J. annua is clearly distinguished by the distribution of hairs in the awn column. Jarava subplumosa and J. psylantha are characterized by the pubescence of the culm, the length of the floret callus,...