P. pratense: stem 1-3 feet high; leaves rough on the edges; spike or spike-like panicle cylindrical, very compact, 1 - 4 inches long; outer glumes truncate at top, with broad scarious edges. - Timothy-grass. - Meadows and pastures. Fl. June to October.
P. arenarium: annual; stem erect, 6-8 inches high; leaves short; spike about an inch long, dense, nearly cylindrical, tapering at the base; spikelets about 1 1/2 line long; outer glumes lanceolate, tapering into a short point. - Maritime sands. Fl. June.
(308) Alopecurus. Fox-tail-grass. * Outer glumes glabrous.
A. agrestis: annual; stem 1-2 feet high, erect, slightly decumbent at the base; leaves short, with long, scarcely loose sheaths; spike 2-3 inches long, thin, tapering; two outer glumes united to about the middle. - Waste places, roadsides, etc. Fl. May to September.
** Outer glumes hairy on the keel.
A. pratensis: stems erect, scarcely decumbent at the base, 1-2 feet high; upper sheaths loose; spike 2-3 inches long, dense, obtuse, hairy; outer glumes free or scarcely united at the base. - Meadows and pastures. Fl. May, June.
A. geniculatus: stem procumbent at the base; upper sheaths loose; spike 1-2 inches' long, cylindrical; outer glumes united at the base. - Moist meadows, marshy places. Fl. June, July. Sometimes the stems thicken at the base into a kind of bulb, and it is then called A. bulbosus.