A phylogeny of species near Agrostis supporting the recognition of two new genera, Agrostula and Alpagrostis (Poaceae, Pooideae, Agrostidinae) from Europe.

Abstract

Based on a molecular DNA phylogeny of three plastid (rpl32-trnK, rps16 intron, and rps16-trnK) and nuclear ITS regions investigating 32 species of Agrostidinae, we describe two new genera, Agrostulagen. nov. with a single species and Alpagrostisgen. nov. with four species; provide support for five species in a monophyletic Podagrostis; and include a small sample of 12 species of a monophyletic Agrostis s.s. (including the type and most species of Neoschischkinia), that separates into two clades corresponding to A.subg.Agrostis and A.subg.Vilfa. Agrostula differs from Agrostis in having leaf blades with pillars of sclerenchyma which are continuous between the adaxial and abaxial surface of the blades, dorsally rounded glumes with blunt to truncate and erose to denticulate apices, florets ½ the length of the glumes, lemmas equally wide as long, widest at (or near) apex, apices broadly truncate, irregularly 5 to 7 denticulate to erose, awnless, anthers longer than the lemmas, and rugose-papillose caryopses. Alpagrostis differs from Agrostis in having geniculate basally inserted awns and truncate lemma apices with lateral veins prolonged from the apex in (2)4 setae. The following eight new combinations are made: Agrostulatruncatula, Agrostulatruncatulasubsp.durieui, Alpagrostisalpina, Alpagrostisalpinavar.flavescens, Alpagrostisbarceloi, Alpagrostissetacea, Alpagrostissetaceavar.flava, and Alpagrostisschleicheri. In addition, we provide a key separating Agrostula and Alpagrostis from Agrostis s.s. and other genera previously considered as synonyms of Agrostis; lectotypify Agrostisalpina Scop., A.schleicheri Jord. & Verl., A.truncatula Parl., and A.truncatulavar.durieui Henriq.; and neotypify A.setacea Curtis.