MOLECULAR PHYLOGENETIC ANALYSIS OF THE AMERICAN STIPEAE (POACEAE) RESOLVES JARAVA SENSU LATO POLYPHYLETIC: EVIDENCE FOR A NEW GENUS, PAPPOSTIPA

A molecular phylogenetic analysis based on plastid ( trnK-matK , matK, trnH-psbA, and trnL-trnF regions) and nuclear ITS DNA sequences of 68 species representing 11 genera suggests an entirely new hypothesis for the evolutionary history within the tribe. Piptochaetium, Anatherostipa, Ptilagrostis and Hesperostipa are basal lineages that diverge independently from a clade that includes a monophyletic Jarava subg. Pappostipa (rendering Jarava s.l. polyphyletic) that is sister group to Austrostipa plus a subclade referred to as the "Major American Clade" (MAC). Within the MAC, New World Achnatherum is the sister group of a grade or clade of Jarava s.s. and a Nassella-Amelichloa clad e. Jarava subg. Pappostipa is monophyletic and not closely related to other sampled species of Jarava, supporting recognition of the new genus Pappostipa (Speg.) Romaschenko, RM. Peterson & Soreng with 23 species; Stipa speciosa selected as the lectotype. Within Pappostipa we identify two clades that we recognize as new sections, and we make new combinations to transfer Jarava subsp. Pappostipa species to the new genus: Pappostipa sect. Chrysovaginatae Romaschenko, with the following new combinations: Pappostipa sorianoi (Parodi) Romaschenko, Pappostipa atacamensis (Parodi) Romaschenko, Pappostipa nana (Speg.) Romaschenko, Pappostipa ibarii (Phil.) Romaschenko, Pappostipa ibarii f. pallescens (Parodi) Romaschenko, Pappostipa ibarii var. anomala (Parodi) Romaschenko, Pappostipa ameghinoi (Speg.) Romaschenko, Pappostipa ameghinoi var. digona (Parodi) Romaschenko, Pappostipa ameghinoi var. precordillerana (F.A. Roig) Romaschenko, Pappostipa chubutensis (Speg.) Romaschenko, Pappostipa chubutensis var. hirsutissima (F.A. Roig) Romaschenko, Pappostipa frigida (Phil.) Romaschenko, Pappostipa frigida var. parvispicula (Parodi) Romaschenko, Pappostipa humilis (Cav.) Romaschenko, Pappostipa humilis var. decrescens (Kuntze) Romaschenko, Pappostipa humilis var. ruiziana (Parodi) Romaschenko, Pappostipa chrysophylla (E. Desv.) Romaschenko, Pappostipa chrysophylla f. minuta (F.A. Roig) Romaschenko, Pappostipa chrysophylla var. cordillerarum (Parodi) Romaschenko, Pappostipa chrysophylla var. crispula (Kuntze) Romaschenko, and Pappostipa chrysophylla f. modica (F.A. Roig) Romaschenko. Pappostipa sect. Pappostipa includes the following new combinations: Pappostipa speciosa (Trin. <Sr Rupr.) Romaschenko, Pappostipa speciosa var. manqueclensis (F.A. Roig) Romaschenko, Pappostipa speciosa var. atuelensis (F.A. Roig) Romaschenko, Pappostipa speciosa var. parva (F.A. Roig) Romaschenko, Pappostipa speciosa var. breviglumis (Parodi) Romaschenko, Pappostipa speciosa var. ciliata (F.A. Roig) Romaschenko, Pappostipa speciosa f. horrida (F.A. Roig) Romaschenko, Pappostipa speciosa f. abscondita (F.A. Roig) Romaschenko, Pappostipa speciosa var. media (Torres) Romaschenko, Pappostipa vaginata (Phil.) Romaschenko, Pappostipa vaginata f. rigida (F.A. Roig) Romaschenko, Pappostipa vaginata f. inmersa (F.A. Roig) Romaschenko, Pappostipa vaginata f. laevis (F.A. Roig) Romaschenko, Pappostipa vaginata f. contracta (F.A. Roig) Romaschenko, Pappostipa vaginata var. argyroidea (F.A. Roig) Romaschenko, Pappostipa vaginata var. dilatata (F.A. Roig) Romaschenko, Pappostipa nicorae (F.A. Roig) Romaschenko, Pappostipa hieronymusii (Pilg.) Romaschenko, Pappostipa patagonica (Speg.) Romaschenko, Pappostipa maeviae (F.A. Roig) Romaschenko,