H. pratense: stems erect or decumbent, two feet high; leaves glabrous and rather narrow; spike 1 1/2-2 inches long, close, cylindrical; flowers of the central spikelet only perfect, the outer glumes of all the spikelets awn-like from the base. - Moist meadows and pastures. Fl. June.
H. murinum: annual; stems decumbent at the base, 1-2 feet long; leaves often hairy; spike dense, cylindrical, 3-4 inches long, thickly beset with the long rough awns; outer glumes of the three spikelets all awn-like, but those of the central spikelet somewhat broader at the base and ciliate. - Mouse Barley. - Waste places, roadsides, etc. Fl. June to August.