* Pales rounded on the back.
P. maritima: stems decumbent or erect, a foot high; leaves short, narrow, usually convolute; panicle erect, rather stiff, 3-4 inches long, the branches erect, or the lower ones spreading; spikelets not numerous, shortly stalked, all turned to one side of the branches. - Maritime sands. Fl. June, July.
P. distans is very near this, but the leaves are flatter, the stems taller and more slender, and the panicle more spreading, with long, slender branches.
P. procumbens is a dwarfer plant, with decumbent stems, 6-8 inches long, flat leaves, and a more compact, branched, one-sided panicle.
P. rigida: annual; stems tufted, six inches high, stiff, erect or slightly decumbent at the base; panicle lanceolate, onesided, about two inches long, rather crowded, the branches slightly spreading. - Waste, dry, or stony places. Fl. June.
** Pales keeled.
P. nemoralis: stems 1-2 feet high, erectish, but weak and slender; leaves narrow; panicle contracted or spreading, with slender branches. - Woods and shady places. Fl. June, July.
P. alpina: stems tufted, 1/2-1 foot high; leaves short, broad, mostly radical; panicle close ovoid, about two inches long, spreading; spikelets crowded, ovate, 3-5-flowered. - Alpine pastures. Fl. June, July.