Mostly perennial grasses with flat leaf-blades and spicate inflorescence, the spikes solitary, few, or numerous and verticillate or approximate. Spikelets 1-flowered, arranged in two rows on one side of the rachis. Scales 4; the 2 lower empty, unequal, keeled, acute; third and fourth usually awned, the former subtending a perfect flower; palet folded and 2-keeled. Stamens 3. Styles distinct. Stigmas plumose. Grain free, enclosed in the scale. [Greek, greenish-yellow, referring to the color of the herbage.]

About forty species, mostly natives of warm and tropical regions. Besides the following some 10 others occur in the southern United States. Type species: Agrostis cruciata L.

1. Chloris Verticillata Nutt. Windmill-Grass. Prairie Chloris. Branching Foxtail

Fig. 544

Chloris verticillata Nutt. Trans. Am. Phil. Soc. (II.) 5: 150. 1833-37.

Culms 6'-18' tall, erect, or decumbent and rooting at the lower nodes, smooth, glabrous. Sheaths shorter than the internodes, smooth, or roughish at the summit; ligule a ring of short hairs; blades i' - 3' long, 1"-2" wide, obtuse, often apiculate, scabrous; spikes slender, usually spreading, 2'-4 1/2' long, in one or two whorls, or the upper ones approximate; spikelets, exclusive of the awns, about 1 1/2" long, the first scale about one-half the length of the second; the third 1" long, obtuse, ciliate on the nerves, especially on the lateral ones, bearing just below the apex a scabrous awn about 2 1/2" long; fourth scale as long as or shorter than the third, awned near the usually truncate apex.

On prairies, Missouri to Colorado and Texas. May-July.

Chloris elegans H.B.K., common from New Mexico to California and southward, has been reported from Kansas. Distinguished from the above by its short stout spikes and the tuft of long hairs at the summit of the lateral nerves of the flowering scales.

1 Chloris Verticillata Nutt Windmill Grass Prairie 544