Jarava, a genus of the tribe Stipeae with 31 American species, is considered polyphyletic. In previous phylogenetic analyses, despite a few species of Jarava were used, they were included in the Major American Clade (MAC) together with species of Achnatherum, Amelichloa and Nassella. The main goal of this study is to test the monophyly of Jarava and to estimate relationships of Jarava species and allied genera. Eighty-nine species of Stipeae (17 species of Jarava) were included in the analyses of trnH-psbA and ITS regions from plastid and nuclear genomes, respectively. Morphological characters were optimized on one of the shortest trees derived from the combined analysis. Jarava splits into different lineages. Jarava ichu, the type species of the genus, and other eight species of Jarava were grouped into subclade B; another four species were associated with Achnatherum in subclade A. Both subclades A and B were included into the MAC. Three species: Jarava neaei, J. psylantha, and J. subplumosa, were grouped with Pappostipa in subclade C. The close relationship between Jarava and Pappostipa appears as a novelty and they should be considered within this genus or recognized as a new genus sister to Pappostipa. The awn indumentum (hair length and position of long hairs, either in part or the entire awn) and the subacute or acute callus are useful to recognize the group (subclade C). Geographical distribution of Jarava from subclade C overlaps completely with that of Pappostipa. The shared geographical distribution is in accordance with major groupings in our phylogenetic topology.
Abstract—Within grasses, the tribe Stipeae is highly specialized by the presence of only one fruit per spikelet and characterized by the diversity in the ornamentation of the floret. Our aim was to analyze similarities and differences based on multi- and univariate analyses among closely related species in American Stipeae: Jarava species with plumose-like awns and species of Pappostipa with pappus-like awns. Ordination analyses (principal coordinate analysis and cluster analysis) were used to determine major groupings, while significant differences among groups were tested by multivariate analysis of variance (MANOVA) and univariate analysis based on generalized linear models (GLM). Based on morphological similarities, we delimited five groups. The presence of a small floret characterized Jarava annua, J. media, and J. plumosula, although J. annua was clearly distinguished by the distribution of hairs in the awn column. Jarava subplumosa and J. psylantha were characterized by the pubescence of the culm, the length of the floret callus, the length of the awn subule, and the length of the awn hairs. Pappostipa was distinctive by having hairs only in the awn column that resemble a pappus while Jarava neaei + J. pogonathera presented the longest inflorescences and hairs only on the awn subule, resembling a feather. As a result, we present a key to taxa and descriptions to characterize and identify species within the Jarava-Pappostipa group with plumose and pappus-like awns.
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