Poa trivialis

HABIT Perennial; caespitose. Stolons present. Culms erect, or geniculately ascending, or decumbent; 20–100 cm long; 3–5 -noded. Culm-internodes terete; smooth. Lateral branches lacking. Leaves mostly basal. Leaf-sheaths keeled; antrorsely scabrous. Ligule an eciliate membrane; 4–10 mm long; acute. Leaf-blades 3–20 cm long; 1.5–6 mm wide. Leaf-blade surface smooth, or scaberulous; glabrous. Leaf-blade apex abruptly acute; hardened.

INFLORESCENCE Inflorescence a panicle.

Panicle open, or contracted; oblong, or ovate; dense, or loose, or effuse; equilateral, or nodding; 3–20 cm long; 1–15 cm wide. Primary panicle branches spreading; 3–7 -nate. Panicle branches flexuous; scaberulous.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels 0.3–2 mm long.

FERTILE SPIKELETS Spikelets comprising 2–4 fertile florets; with diminished florets at the apex. Spikelets elliptic, or oblong, or ovate; laterally compressed; 3–4 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes obscured by lemmas; smooth. Floret callus woolly.

GLUMES Glumes persistent; similar; shorter than spikelet. Lower glume lanceolate; 2–3 mm long; 0.8 length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume primary vein scaberulous. Lower glume lateral veins absent. Lower glume apex acute. Upper glume ovate; 2.5–3.5 mm long; 1 length of adjacent fertile lemma; membranous; 1-keeled; 3 -veined. Upper glume primary vein scabrous. Upper glume apex acute.

FLORETS Fertile lemma ovate; oblong in profile; 2.5–3.5 mm long; membranous; much thinner above; much thinner on margins; keeled; 5 -veined. Lemma midvein ciliolate; hairy below. Lemma lateral veins distinct; stopping well short of apex. Lemma apex acute. Palea 1 length of lemma. Palea keels scabrous. Apical sterile florets resembling fertile though underdeveloped.

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

FRUIT Caryopsis with adherent pericarp. Hilum punctiform.

DISTRIBUTION Europe: northern, central, southwestern, southeastern, and eastern. Africa: north, Macaronesia, and south. Asia-temperate: Siberia, Soviet far east, Soviet Middle Asia, Caucasus, western Asia, China, and eastern Asia. Asia-tropical: India and Malesia. Australasia: Australia and New Zealand. North America: Subarctic, western Canada, eastern Canada, northwest USA, north-central USA, northeast USA, southwest USA, and southeast USA. South America: Mesoamericana, western South America, and southern South America. Antarctic: Subantarctic islands.

NOTES Poeae. CEH.

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