Alopecurus geniculatus L.
kneed foxtail
Perennials; culms spreading from geniculate base and rooting at nodes. Leaf-sheath light green, glabrous, striate, lower sheaths purplish. Ligule (1.5)-2-4.5 mm, membranous, blunt, or tapering above to a point, entire, glabrous, but abaxially with short fine hairs near base. Leaf-blade 4-12 cm × 1.5-2.5 mm, flat, dark green to occasionally glaucous, finely ribbed, finely scabrid on ribs and margins, prickle-teeth not so evident abaxially, tapering to acute tip. Culm (12)-20-30 cm, internodes ridged, glabrous. Panicle 2-4 cm, spike-like, with densely crowded light green to purplish spikelets. Glumes (2)-2.5-3 mm, ± equal, 3-nerved, narrowly elliptic-oblong, blunt, membranous, short hairy, keeled, keel silky-ciliate, margins united near base. Lemma 2-3 mm, ≈ glumes, 4-nerved, broadly oblong or ovate, thinly membranous, glabrous except for a few hairs on margins at very blunt apex, keeled, margins united for short distance below; awn fine, 2.5-4.5 mm, inserted near base, projecting 1.4-2.5 mm beyond glumes. Palea 0. Anthers 1-1.7 mm, yellow or purple. Caryopsis 1.2-1.5 × 0.5-0.8 mm.
N.; S.: throughout; St.; Ch., A., C. Widespread in damp, waste ground, along drains, swamp edges, on river flats and in brackish lagoon margins, in drained pools and shingle pits, the stems often floating in water, rarely on dry shingly roadsides; coastal and inland.
Naturalised from Eurasia.
