Annual or perennial tufted grasses with flat or bristle-like leaves and paniculate inflorescence. Spikelets 1-flowered. Scales 3; the 2 outer empty, membranous, keeled, acute; the third shorter, obtuse, hyaline, sometimes bearing a dorsal awn, subtending a perfect flower; palet shorter than the scale, sometimes minute or wanting. Stamens usually 3. Styles distinct, short. Stigmas plumose. Grain free, enclosed in the scale. Seed adherent to the pericarp. [Name Greek, referring to the field habitat of many species.]

A genus of about 100 species, distributed throughout the world, numerous in temperate regions; 15 others are found in western North America. Type species: Agrostis alba L.

Palet conspicuous, at least one-half as long as the scale.

Panicle open in flower, branches long and spreading; an upland grass. 1. A. alba.

Panicle dense and contracted, spike-like, its branches short and appressed; a grass of brackish

marshes and wet sands.


A. maritima.

Palet inconpicuous, minute, or wanting.

Branches of the contracted panicle short, spikelet-bearing to the base.


A. asperifolia.

Branches of the panicle slender, naked below.

Flowering scale awned.

Awn flexuous, barbellate, twice the length of the 3/4," spikelet.


A. Elliottiana.

Awn stouter, glabrous, rigid, usually bent, not twice the length of the spikelet.

Branches of the panicle usually ascending; spikelets 1" long.

Culms 6' tall or less; panicle 1' long or less; alpine grass.


A. rupestris.

Culms 1°-2° tall; panicle exceeding 2' long.


A. canina.

Branches of the mature panicle spreading; spikelets 1 1/4'-1 1/2" long.

Awn exserted; panicle branches glabrous or hispidulous.-


A. borealis.

Awn short; panicle branches hispid.


A. geminata.

Flowering scale awnless, or very rarely with a short awn.

Culms weak, decumbent or prostrate at the base; blades lax.


A. Schweinitzii.

Culms and blades erect.

Branches of the panicle capillary, elongated, usually dividing above the middle, the spikelets often crowded at the extremities.

Spikelets 3/4"-1" long; blades short.


A. hyemalis.

Spikelets 1 1/4"-1 1/2" long; blades elongated.


A. altissima.

Branches of the panicle not elongated, usually dividing at or below the middle.

Spikelets about 1" long; a grass of low elevations.


A. perennans.

Spikelets 1 1/4"- 1 1/2" long; a high mountain grass.


A. oreophila.