Alpagrostis P.M. Peterson, Romasch., Soreng & Sylvester, 2020

Peterson, Paul M., Sylvester, Steven P., Romaschenko, Konstantin, Soreng, Robert J., Barbera, Patricia, Quintanar, Alejandro & Aedo, Carlos, 2020, A phylogeny of species near Agrostis supporting the recognition of two new genera, Agrostula and Alpagrostis (Poaceae, Pooideae, Agrostidinae) from Europe, PhytoKeys 167, pp. 57-82 : 57

Alpagrostis P.M. Peterson, Romasch., Soreng & Sylvester gen. nov.

Type.

Agrostis alpina Scop.

Diagnosis.

The species of Alpagrostis differ from Agrostis by a combination of characters in having plants densely tufted with only intravaginal innovations, leaves mainly basal, basal leaf blades involute and setaceous or filiform, conduplicate and acute, 0.1-1.2 mm in diameter as folded or rolled, ligules longer than they are wide, spikelets generally> 3 mm long, lemma apices truncate with lateral veins prolonged from the apex in 2 ( A. setacea ) or 4 setae 0.1-0.5 mm long, and, crucially, and lemmas with a well-developed awn, 3-7.4 mm long, inserted basally c. 0.1-0.4 mm from the base of the lemma, conspicuously twisted and geniculate.

Description.

Perennials, densely tufted. Culms 4-75 cm tall, erect or slightly geniculate at the base, slender, smooth or scabrous in the upper part, usually with 2-3 nodes extended above the basal foliage. Tillers intravaginal, extravaginal innovations absent. Leaves mostly basal, in fascicles of few to many leaves; sheaths shorter than the internodes, glabrous, smooth or scabrous; ligules 0.4-5 mm long, longer than they are wide, oblong, hyaline, glabrous, smooth, apices truncate, subacute, acute, entire to dentate; basal and tiller ligules 0.4-3 × 0.15-1.3 mm; upper culm ligules 1.7-5 × 0.7-1.5 mm; blades involute and setaceous or filiform and acute, tender to firm, straight to recurved, glabrous, abaxially smooth to scabrous, adaxially scabrous; blades of the lower culms and tillers 2-25 cm long, 0.1-1.2 mm in diameter as folded or rolled; blades of upper culm 1.5-10 cm long, 0.2-1.5 mm in diameter as folded or rolled, generally wider and shorter than tillers. Inflorescence (1.5-)2-15 × 0.5-3.5 cm, a panicle, lax and open to loosely to densely contracted and spikelike; panicle branches erect, ascendant or patent, with spikelets present from the base to only in the distal ½, glabrous, densely scabrous (or smooth in A. barceloi ); pedicels as long as the spikelets, cylindrical, apices clavate, glabrous, densely scabrous (or smooth in A. barceloi ). Spikelets (2.7 in A. barceloi -)3-5.2(-5.5) mm long, 1-flowered, disarticulating above the glumes, weakly laterally compressed; glumes unequal, the lower shorter and thinner than the upper, upper glume longer than the length of the floret by c. 0.8-1.9 mm, lanceolate, membranous, glabrous, keel scabrous throughout or in the distal ½, lateral veins smooth or scabrous distally, surfaces smooth or scabrous distally, apices acute or mucronate; lower glume 1-veined; upper glume (1-veined in A. barceloi ) 3-veined; floret sessile, much shorter than the glumes; lemmas (1.8 in A. barceloi -)2-3.7, lanceolate, membranous, dorsally rounded, 5-veined, veins usually evident to distinct, with at least the outer veins excurrent, glabrous or thinly pubescent at the base with hairs up to 0.4 mm long, surface smooth to densely scabrous with aculeate (thin short stiff) prickles throughout, apex truncate with lateral veins prolonged from the apex in 2 ( A. setacea ) or 4 setae 0.1-0.5 mm long, awned with awn inserted basally c. 0.1-0.4 mm from the base of the lemma (or sometimes in the lower 1/5-1/4 in A. barceloi ), awn well-developed, 3-7.4 mm long, surpassing the glumes, geniculate in roughly the middle, distinctly twisted proximally with usually at least 2 full twists below the bend, smooth proximally, scabrous distally or for most of the length; paleas 0.4-1 mm long, 1/5-1/3 the length of the lemma, glabrous, smooth, apices bifid, dentate, irregularly dentate or emarginate; calluses rounded, blunt, pilose, with hairs 0.3-0.7 mm long inserted all around or in 2 lateral tufts, abaxially smooth; rachilla prolongation absent. Flowers perfect; lodicules 0.4-0.6 mm long, ½ -2/3 as long as the palea, 2 in number, acute to lanceolate; anthers 0.7-2.3 mm long, 3 in number; ovaries glabrous. Caryopses 1.7-2 mm long, shorter than the lemmas, concealed at maturity, ellipsoid or fusiform, surface smooth (becoming narrow and shriveled with age), ventrally sulcate, sulcus distinct, almost without rostellum; hilum 1/6-1/3 length of the caryopsis, narrowly elliptic; endosperm liquid. 2 n = 14 (In A. setacea , A. alpina ), 28 ( A. barceloi ), or 42 ( A. schleicheri ) [ Frey 1997; Sáez and Rosselló 2000].

Distribution and ecology.

Europe and Mediterranean. Found in cold temperate, often high-elevation environments, often found growing on nutrient poor soils. Usually flowering from June to August.

Notes.

All caryopses examined from herbarium specimens had a liquid lipid endosperm or were shriveled with a deep sulcus, implying that fresher specimens likely had a liquid endosperm. Agrostis sect. Bromidium (Nees & Meyen) E. Desv. shares many characteristics with Alpagrostis , such as lemma apices terminating in scabrous setae, well-developed, thickened, twisted and geniculate awns inserted in the lower 1/3 of the lemma, palea <1/3 the length of the lemma, caryopses with liquid to semi-liquid endosperm. Based on molecular DNA studies, Romaschenko et al. (unpubl.) and Tkach et al. (2020) found Bromidium to align within Agrostis s.s.

Alpagrostis barceloi differs somewhat from the other species in the genus, in terms of the panicle branches and pedicels being smooth, spikelets sometimes being shorter, 1-veined upper glumes, and awn sometimes inserted slightly higher up the lemma.