Side-oats Grama

The perennial grass is about 2–2½’ tall and unbranched. The culms are light green, glabrous, and terete (round in cross-section); later during the autumn after a hard frost, they become light tan. The alternate leaves are more common toward the base of each culm. The leaf blades are up to 8″ long and ¼” (6 mm.) across; they are light green to blue-green, mostly hairless, and rough-textured along their margins. However, near the bases of leaf blades, there are often scattered white hairs. The larger leaf blades often have prominent central veins. The open leaf sheaths are light green to blue-green, longitudinally veined, and mostly hairless, although scattered white hairs sometimes occur near their apices and along their upper margins. Each ligule consists of a ring of short fine hairs. The nodes are slightly swollen, rough, and often reddish or brownish green; the portion of the culm near each node may be tinted similarly as well. The culm terminates in a narrow raceme up to 10″ long that consists of 25-50 floral spikes that are pendulous; these spikes are pale green, pale red, or greenish red during the blooming period, although they later become light tan.

Each spike is about ½” (12 mm.) long, consisting of 3-7 sessile adjacent spikelets. Each spikelet consists of a pair of linear-lanceolate glumes and a pair of linear-lanceolate lemmas; only one of the lemmas is fertile. Individual spikelets, excluding any awns, are up to 1/3″ (8 mm.) long. The glumes have acute tips, while the tips of lemmas are often notched on either side; the infertile lemma has an awn up to ¼” (6 mm.) in length, while the fertile lemma is awnless. The colorful anthers of fertile lemmas are orange to brownish red, while their stigmata are white and feathery. The blooming period occurs from mid-summer to early fall. The spikes of the inflorescence persist into the autumn, after which they fall to the ground in their entirety. Each fertile lemma produces a single grain. Mature grains are about 4.5 mm. long, 1.5 mm. across, narrowly ellipsoid in shape, and light tan. The root system is fibrous and rhizomatous. Side Oats Grama often forms tight bunches of culms from its rhizomes, although it also occurs as scattered plants. In moist areas where there is little competition, it may form a dense sod.