Plants perennial; cespitose, not rhizomatous. Culms 20-100
cm, erect, sometimes decumbent; lower internodes densely pilose,
with hairs to 1 mm; uppermost internode often glabrous. Sheaths densely
pubescent; ligules 1-4 mm, truncate, erose-ciliolate; blades 2-20
cm long, (3)5-10 mm wide, densely soft-pubescent. Panicles 3-15(20)
cm long, 1-8 cm wide; branches hirsute; pedicels 0.2-1.6(4)
mm, pilose, hairs to 0.3 mm. Spikelets 3-6 mm; rachillas 0.4-0.5
mm, glabrous. Glumes exceeding and enclosing the florets, membranous,
ciliate on the keels and veins, usually scabrous, puberulent, or villous
between the veins, especially towards the apices, whitish-green, often
purple over the veins and towards the apices; lower glumes lanceolate,
narrow, acute; upper glumes ovate, wider and longer than the lower
glumes, midveins often prolonged as an awn to 1.5 mm, apices obtuse, somewhat
bifid; calluses sparsely hirsute; lemmas 1.7-2.5 mm, acute,
erose-ciliate; upper lemmas shallowly bifid, awns 1-2 mm, often
purple-tipped, slightly twisted and strongly hooked at maturity; anthers (1.2)2-2.5
mm. 2n = 14.
Holcus lanatus grows in disturbed sites, moist waste places, lawns,
and pastures, in a wide range of edaphic conditions and at elevations from
0-2300 m. A native of Europe, it was widely distributed in North America
by 1800. It is an ancestor of the polyploid complex represented by Holcus
mollis. In Europe, it hybridizes with tetraploids of H. mollis to
form a sterile triploid that spreads vegetatively.
Culms 4-10 dm, without rhizomes, soft-villous below, the upper internode usually glabrous; sheaths soft-hairy; blades pale green, soft-hairy, 4-10 mm wide; infl narrowly ovoid, dense, 5-15 cm; glumes 4-5 mm, acute, villous on the surface, short-hirsute on the veins; lemmas smooth and shining, 2 mm, obtuse, the awn of the upper one hooked, 1-2 mm, scarcely exserted from the glumes; 2n=14. Meadows and roadsides in moist soil; native of Europe, now well established throughout our range.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.