Flora of North America species comparison

15-130 cm, slender to stout, not woody, erect to decumbent, straight to zigzag, simple to profusely branched;

nodes sparsely to densely pilose.

50-140 cm tall, 1.5-2.5 mm thick, usually erect, rarely decumbent, firm;

nodes glabrous or puberulent;

internodes glabrous.

rounded, hirsute or hispid, hairs papillose-based;

ligules membranous, ciliate, cilia 0.5-1.5 mm;

blades 5-40 cm long, 3-18 mm wide, linear, spreading.

shorter than the internodes, glabrous or hispid, hairs papillose-based, rounded basally;

ligules 0.5-2 mm;

blades 10-30 cm long, 2-8 mm wide, flat, glabrous or sparsely hirsute on 1 or both surfaces.

13-50 cm long, 7-24 cm wide, usually more than 1/2 as long as the plants, included at the base or exserted at maturity, disarticulating at the base of the peduncles at maturity and becoming a tumbleweed;

branches spreading;

pedicels 0.5-2.8 mm, scabrous, pilose.

4-25(40) cm long, 3-14 cm wide, exerted, lax;

primary branches 3-14 cm, opposite and alternate, ascending, glabrous, branching in the distal M;

pedicels 1-4 mm, appressed or spreading.

1.9-4 mm, ellipsoid to lanceoloid, often red-purple, glabrous.

2.5-3.5 mm long, 1-1.2 mm wide, narrowly ovoid to ellipsoid, glabrous, acute.

1-1.5 mm, about 1/3 as long as the spikelets, glabrous, 1-3-veined, acute;

upper glumes slightly exceeding the lower lemmas, glabrous, acute, scarcely separated from the lower lemmas;

lower florets staminate;

lower lemmas similar to the upper glumes;

lower paleas 2-3 mm, oblong;

upper florets 2-2.5 mm long, 0.8-1 mm wide, ellipsoid, widest below the middle, glabrous, smooth, shiny, apices lightly beaked.

florets sterile;

lower glumes 1/3– 1/2 as long as the spikelets, 1-3-veined;

upper glumes 1.8-3.1 mm, 7-9-veined, midveins scabridulous;

lower lemmas 1.9-3 mm, extending 0.4-1.1 mm beyond the upper florets, often stiff, straight, prominently veined distally;

upper florets stramineous or nigrescent, sometimes with a prominent lunate scar at the base, often disarticulating before the glumes, leaving the empty glumes and lower lemmas temporarily persisting on the panicles.

= 18.

= 18, 36, 41, 42, 43, 45, 54, 63 (United States material apparently usually tetraploid, with 2n = 36).