Perennial grasses with narrow flat leaf-blades and an inflorescence composed of numerous short scattered 1-sided spreading or reflexed spikes. Spikelets 1-flowered, crowded in 2 rows, sessile, imbricated, the rachilla articulated above the empty scales and extending beyond the flower, its summit bearing scales or awns. Scales 3 or more, the lower 2 empty, unequal, acute, narrow, keeled, the third scale thicker and broader, enclosing a narrow 2-toothed hyaline palet and a perfect flower, 3-toothed at the apex, the teeth more or less awned, the small upper scales minute, awned. Stamens 3. Styles distinct. Stigmas plumose. Grain free, enclosed in the scale. [Greek, in reference to the awns of the flowering scales.]

Species about 15, natives of temperate and tropical regions. Type species: Atheropogon apludoides Muhl.

1. Atheropogon Curtipendulus (Michx.) Fourn. Tall Grama-Grass

Fig. 550

Chloris curtipendula Michx. Fl. Bor. Am. 1: 59. 1803. Bouteloua racemosa Lag. Van Cienc. y Litter. 2: Part 4, 141. 1805. Bouteloua curtipendula Torr. Emory's Rep. 153. 1848. Atheropogon curtipendulus Fourn. Mex. PI. Gram. 138.

1881.

Culms 1°-3° tall, erect, simple, smooth and glabrous. Sheaths shorter than the internodes; ligule a ring of short hairs; leaves 2-12' long, 2" wide or less, flat or involute, rough, especially above; spikes numerous, 3"-8" long, widely spreading or reflexed; spikelets 4-12, divergent from the rachis, 3 1/2" - 5" long, scales scabrous, especially on the keel, the first shorter than or equalling the second; the third 3-toothed, the nerves extended into short awns; rachilla bearing at the summit a small awned scale, or sometimes a larger 3-nerved scale, the nerves extended into awns; anthers vermilion or cinnabar-red.

In dry soil, Connecticut to North Dakota and Wyoming, south to New Jersey, Tennessee, Mississippi and Mexico. Side-oats Grama, Mesquite-grass. July-Sept.