Poa (Alpinae) Soreng, L. J. Gillespie & Cabi

Poa subg. Alpinae (Hegetschw. ex Nyman) Soreng, L. J. Gillespie & Cabi, stat. et subg. nov. ≡ Poa [unranked] Alpinae Hegetschw. ex Nyman, Consp. Fl. Eur. 4: 835. 1882. ≡ Poa sect. Alpinae (Hegetschw. ex Nyman) Stapf, Fl. Brit. India 7 (22): 338. 1896 [‘ 1897 ']. ≡ Poa ser. Alpinae Roshev., Fl. SSSR 2: 411. 1934. Type. Poa alpina L., Sp. Pl. 1: 67. 1753. Description. Perennials; hermaphroditic; tufts dense (infrequently weakly short stooling), compact; vegetative branching intravaginal, with or without bulbs; prophylls elongated; bulbs present or absent. Culms generally 10–40 (– 70 cm) tall, terete, smooth or infrequently lightly scabrous, rarely densely scabrous, with 1 (– 2) nodes exposed. Leaves mostly basal; flag - leaf sheath margins fused from the base for 1 / 4–1 / 2 their length; ligules (0.4 –) 1–6 (– 10) mm long, usually obtuse to acute, usually smooth, apex entire or sometimes tripartite, eciliolate; blades usually (0.5 –) 1–2.5 mm wide, keeled, flat, or more often v-shaped or folded, thin and flaccid in age to fairly firm, persistent. Panicles usually short and more or less contracted (often open in flowering); branches usually few, usually ascending, terete, usually smooth or lightly scabrous (rarely densely scabrous). Spikelets laterally compressed, keeled, usually ovate in outline with (2 –) 3–5 (– 10) florets, in some species frequently developing into vegetative bulbils; bract edges usually with sparse, short prickles; glumes slightly thinner than the lemmas, usually scabrous along the keel, apex and upper margins scarious; lower glumes usually 2 / 3–3 / 4 the first lemma in length, 1–3 veined; upper glumes usually subequaling first lemma in length; rachillas terete, smooth, glabrous, infrequently softly pubescent; callus dorsally, sightly laterally pinched, glabrous or sometimes with a dorsal tuft of hairs (webbed); lemmas keeled, 3–5 veined, intermediate veins absent, obscure, or faint, keel and marginal veins usually softly pubescent, hairs slightly inflated above with round apices, infrequently glabrous throughout (P. bactriana, rarely so in other species), between the veins glabrous or sometimes puberulent; apex and upper margins glabrous, usually broadly scarious; palea keels scabrous, glabrous or sometimes pubescent in the mid-section. Flowers of normal florets unisexual; anthers 3, mostly 1–2 mm long. Clade code: Aa. Comments. Soreng (1998) rejected the lectotypification by Edmondson (1978) of P. sect. Bolbophorum, on Poa alpina L. over the Type identified by Ascherson and Graebner (1900). All members treated here belong to DNA Aa - clade. The bulbous taxa are intermixed with non-bulbous taxa in subg. Alpinae, and all are placed in one section, but for convenience they are placed in separate series Bulbosae and Alpinae. Poa ligulata (a diploid species endemic to mountains of the Iberian Peninsula and northwest Africa), although usually placed in sect. Alpinae s. s. is intermediate in form, having broad and slightly thickened basal sheaths. Possibly P. ligulata is the progenitor of bulbs in the subgenus. It resolved as sister to Poa badensis in IE trees but aligned in a polytomy with two P. bulbosa samples (originating from Spain and Turkey) and the remainder of the A - clade in plastid trees. Callus hairs in P. subg. Alpinae, when present, are restricted to the dorsal side and form a soft sinuous tuft, mostly longer than the hairs of the keel. Callus hairs are rare and sparse when present in series Alpinae. Only a few taxa of series Bulbosae have callus hairs (P. bulbosa var. bulbosa and var. perligulata, which are sparse or absent in P. perconcinna. Variations in floret hair apices in Poa are illustrated by Chrtek and Jirásek (1965).