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.

40-100 cm, erect, simple or branching from the lower nodes;

nodes glabrous;

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, usually glabrous, lower sheaths sometimes pilose at the summit, hairs papillose-based;

ligules 0.1-0.4 mm;

blades 4-19 cm long, 1.5-4 mm wide, mostly involute at maturity, erect, firm, abaxial surfaces usually glabrous, adaxial surfaces often sparsely pilose, particularly basally.

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.

3-12 cm long, less than 1 cm wide, contracted, with few spikelets;

branches 1-4 cm, few, ascending-appressed; ultimate branchlets 1-sided;

pedicels 0.5-3 mm, scabridulous, appressed, usually with a few slender hairs at the apices.

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

1.8-2.8 mm long, 0.8-1 mm wide, usually subsessile, lanceoloid to narrowly ovoid, green, often purplish-stained, glabrous, acute.

0.9-3 mm, 1/2 - 2/3 as long as the spikelets, 1-3-veined, not keeled over the midveins, acute or obtuse;

upper glumes and lower lemmas subequal, 5-7-veined, midveins not keeled, acute to short-acuminate, occasionally gaping at the apices;

lower florets sterile;

lower paleas about 1/2 - 2/3 as long as the lower lemmas;

upper florets 1.1-1.8 mm long, 0.6-0.8 mm wide, 2/5 – 3/4 as long as the spikelets, lustrous, usually brownish, apices glabrous;

upper lemmas thick, stiff, clasping the upper paleas throughout their length.

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.

= 20.