Poa annua L.
annual poa
Loosely to compactly tufted, usually bright green annual, to 35 cm, or short-lived perennial; branching intravaginal; leaf-blades persistent. Leaf-sheath pale green, hyaline, glabrous, keeled. Ligule 0.5-2 mm, entire, rounded, glabrous throughout. Leaf-blade 1.5-9 cm × 3-4 mm, flat or folded, soft, glabrous, often crinkled when young; margins sparsely, minutely scabrid, tip rounded to blunt point. Culm 3-20 cm, erect, spreading or prostrate, internodes glabrous. Panicle 2-10 cm, usually open, erect; branches smooth to sparsely scabrid, spreading to deflexed after anthesis. Spikelets 4-6 mm, with 3-6 crowded florets, light green or sometimes purplish. Glumes ± unequal, glabrous; lower 1.5-2.5 mm, 1-nerved, lanceolate to ovate, acute, upper 2-3 mm, 3-nerved, elliptic to oblong, subobtuse. Lemma 3-3.5 mm, 5-nerved, nerves densely hairy for about ½ length and glabrous above hairs, internerves glabrous, rarely lemma entirely glabrous, purplish just below hyaline band at obtuse tip. Palea 2.5-3 mm, keels long-ciliate, or rarely glabrous, interkeel glabrous. Callus glabrous. Rachilla 0.5-1 mm, glabrous; prolongation much shorter. Lodicules 0.3 mm. Gynomonoecious: each spikelet with 2-3 lower flowers ⚥, anthers (0.6)-0.7-1 mm, gynoecium 1-1.5 mm; upper flowers ♀, pollen-sterile anthers to 0.2 mm or 0, gynoecium c. 1.5 mm. Caryopsis c. 1.5 × 0.5 mm, tightly enclosed by anthoecium.
N.; S.: throughout; St.; K., Ch., Sn., Ant., A., C., M. A weed of cultivated land and waste places throughout. FL Jan-Dec.
Naturalised from Europe.
Cosmopolitan and weedy.
