E-Flora BC: Electronic Atlas of the Flora of British Columbia

General:
Perennial grass from scaly rhizomes; stems hollow, erect, slightly compressed, unbranched or sparingly branched, the internodes dull, finely short-hairy, 30-120 cm tall.

Leaves:
Sheaths minutely rough, slightly keeled, appressed-hairy at base; blades flat, 2-6 mm wide, 2-15 cm long, minutely rough or occasionally smooth; ligules membranous, jagged to more or less fringed with fine hairs, the tips squared-off, 0.2-0.6 mm long.

Flowers:
Inflorescence a narrow, condensed, spikelike, densely flowered, somewhat lobed panicle, 1.5-12 cm long, 0.3-1.8 cm wide, the branches tightly appressed, 0.2-2.5 cm long, the spikelets densely clustered; spikelets 1-flowered, nearly unstalked to short-stalked; glumes narrow, awl-pointed, 1-nerved, smooth to minutely rough near the tips, nearly equal, usually 1.3-2 times longer than the lemmas, (3) 4-7 (8) mm long, the tips long-pointed, tapering into short awns up to 5 mm long; lemmas lanceolate, 3-nerved, short soft-hairy along the midnerves, margins and at the base, minutely rough near the tips, 1.9-3.1 mm long, the tips long-pointed, unawned or short awn-tipped, the awns up to 1 mm long, minutely rough, the calluses bearded, the hairs short soft-hairy, about 1 mm long; paleas lanceolate, loosely soft-hairy between nerves, about the same length as the lemmas, the tips long-pointed; anthers about 0.8-1.5 mm long, yellowish.

Notes:
This species has been studied cytologically and most populations appear to be diploid (2n=20) whereas two close relatives, M. mexicana and M. racemosa, are tetraploids (2n=40). Separation of these taxa is often problematic and major differences are emphasized in the key.