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.

35-150 cm, stout, compressed.

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.

more or less strongly compressed or keeled, sides usually glabrous or sparsely pubescent distally;

ligules 0.3-3 mm, membranous, erose or ciliate, cilia often themselves fimbriate;

blades 8-50 cm long, 2-12 mm wide, flat or folded, both surfaces usually glabrous or scabridulous, or the adaxial surfaces sparsely pilose 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.

terminal and axillary, 9-40 cm, 1/3 – 3/4 as wide as long, usually dense; ultimate branchlets usually appressed, 1-sided, scabridulous;

pedicels 0.5-1.5 mm, usually appressed, sometimes with 1-several slender hairs at the apices.

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

usually 1.6-3.8 mm, usually subsessile, lanceolate, green, purple-tinged, or purple, glabrous.

2/5 – 3/4 as long as the spikelets, 3-veined, midveins keeled;

upper glumes and lower lemmas subequal or the glumes slightly longer, often spreading slightly apart at the apices, midveins keeled, usually scabridulous apically;

lower florets sterile;

lower paleas to 2/3 as long as the lower lemmas;

upper florets 1.4-2 mm long, 0.6-0.8 mm wide, 2/5 – 3/4 as long as the spikelets, occasionally stipitate, lustrous, with a tuft of minute, thickish hairs at the apices;

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.

=18.