Poa alpina

HABIT Perennial; caespitose. Rhizomes absent, or short. Butt sheaths herbaceous; persistent and investing base of culm; with compacted dead sheaths. Culms erect, or geniculately ascending; 5–40 cm long; 1–2 -noded. Culm-internodes terete; smooth. Lateral branches lacking. Leaves mostly basal. Leaf-sheaths without keel; smooth. Ligule an eciliate membrane; 3–6 mm long; obtuse, or acute. Leaf-blades flat, or conduplicate; 2–12 cm long; 2–5 mm wide. Leaf-blade surface smooth; glabrous. Leaf-blade margins smooth, or scaberulous. Leaf-blade apex obtuse, or abruptly acute; hooded.

INFLORESCENCE Inflorescence a panicle.

Panicle open; ovate; dense, or loose; equilateral, or nodding; 3–7 cm long; 3–7 cm wide. Primary panicle branches spreading; 2 -nate. Panicle branches scaberulous.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels 0.5–2 mm long.

FERTILE SPIKELETS Spikelets comprising 2–5 fertile florets; with diminished florets at the apex. Spikelets oblong, or ovate; laterally compressed; 4–7 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes definite; obscured by lemmas; smooth. Floret callus pubescent.

GLUMES Glumes persistent; similar; shorter than spikelet. Lower glume elliptic, or ovate; 2.5–4 mm long; 0.8–0.9 length of upper glume; membranous; much thinner on margins; 1-keeled; 1–3 -veined. Lower glume primary vein scabrous. Lower glume apex acute. Upper glume elliptic, or ovate; 3–4.5 mm long; 0.8–0.9 length of adjacent fertile lemma; membranous; with hyaline margins; 1-keeled; 3 -veined. Upper glume primary vein scabrous. Upper glume apex acute.

FLORETS Fertile lemma ovate; elliptic in profile; 3.5–5 mm long; membranous; much thinner above; keeled; 5 -veined. Lemma midvein ciliate; hairy below. Lemma lateral veins stopping well short of apex. Lemma surface scaberulous; pubescent; hairy on veins. Lemma margins ciliate; hairy below. Lemma apex acute. Palea 1 length of lemma. Palea keels ciliolate; adorned in the middle. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 2; membranous. Anthers 3; 1.5–2.5 mm long.

FRUIT Caryopsis with adherent pericarp. Hilum punctiform.

CLEISTOGENES AND VIVIPARY Vegetative proliferation occurs.

DISTRIBUTION Europe: northern, central, southwestern, southeastern, and eastern. Africa: north. Asia-temperate: Siberia, Soviet far east, Soviet Middle Asia, Caucasus, western Asia, China, Mongolia, and eastern Asia. Asia-tropical: India. North America: Subarctic, western Canada, eastern Canada, northwest USA, and southwest USA.

NOTES Poeae. CEH.

Please cite this publication as detailed in How to Cite Version: 3rd February 2016.