Holcus mollis
Plants perennial; not cespitose, rhizomatous, rhizomes to 40 cm. Culms 20-100(150) cm, usually decumbent at the base; lower internodes glabrous or sparsely pubescent. Sheaths glabrous or hairy; ligules 1-5 mm, obtuse, erose; blades 2-20 cm long, 3-10 mm wide, pubescent. Panicles 4-20(22) cm long, to 3 cm wide; branches puberulent or ciliate; pedicels to 5 mm long, pilose, hairs to 0.3 mm. Spikelets 4-6(7) mm; rachillas hairy. Glumes exceeding and enclosing the florets, subequal, nearly the same width, ovate, membranous, whitish green when young, straw-colored with age, veins ciliate, often purple, intercostal regions scabrous or glabrous, apices acuminate or acute, unawned; calluses densely to sparsely hairy; lemmas 2-2.5 mm, glabrous, acute; upper lemmas bifid, awned above midlength, awns 3-5 mm, scabrous, straight or geniculate at maturity; anthers about 2 mm. 2n = 28 (35, 42, 49).
Distribution
N.H., N.J., Wash., Del., N.C., Calif., Oreg., N.Y., Pa., Vt., Idaho, B.C., Nfld. And Labr. (Labr.)
Discussion
Holcus mollis grows in moist soil and disturbed sites, including lawns and damp pastures. It is a European introduction that has persisted in the Flora region, becoming a problematic weed in ungrazed pastures, prairie remnants, and oak savannahs in portions of the Pacific Northwest. It is also sold as an ornamental. There are two subspecies: Holcus mollis L. subsp. mollis (stems not thickened and tuberous at the base; panicles lax, brownish or purplish) and H. mollis subsp. reuteri (Boiss.) Malag. (stems thickened and tuberous at the base; panicles narrow, whitish). North American introductions belong to subsp. mollis.
Selected References
None.