Flora of North America species comparison

(10)50-140 cm, stout, stiffly erect, branched from the middle and lower nodes;

lower nodes sericeous;

lower internodes sericeous, hairs papillose-based, upper internodes sometimes glabrous.

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

nodes glabrous or puberulent;

internodes glabrous.

rounded, glabrous or sparsely to densely hispid, hairs not fragile and prickly, not causing skin irritation, margins ciliate;

ligules 1-3 mm;

blades 3-60 cm long, 2-12 mm wide, flat or involute, ascending, adaxial surfaces densely hirsute basally, less densely so elsewhere, bases attenuate, apices acute.

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.

(4)15-40 cm long, (3)10-25 cm wide, about 1/3 – 1/2 as long as the plants, open, breaking at the base of the peduncles at maturity and dispersed as tumbleweeds, secondary branching mostly confined to the distal 1/3 of the primary branches;

rachises densely hispid or glabrous;

lower primary branches in whorls of 4-7, stiffly spreading, naked on the lower 1/2;

pedicels 3-20 mm, appressed.

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.

2-3 mm long, 0.8-1.2 mm wide, glabrous.

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

1-1.6 mm, 5-veined, acuminate;

upper glumes and lower lemmas similar, 2-2.8 mm, 7-9-veined, exceeding the upper florets by about 0.3 mm;

lower florets sterile;

lower paleas 1.4-2.2 mm;

upper florets 1.5-1.9 mm long, 0.7-1 mm wide, smooth, chestnut brown at maturity.

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.

= 36.

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