Flora of North America species comparison

8-100 cm tall, about 1 mm thick, erect to decumbent, simple to profusely branched;

nodes sparsely to densely pilose.

(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.

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.

often crowded basally;

sheaths rounded, usually longer than the internodes, hispid, hairs papillose-based, to 5 mm;

ligules 0.5-1.5 mm;

blades 3-30 cm long, 2-12 mm wide, linear, ascending to erect, flat, hirsute to sparsely pilose, greenish or purplish, bases truncate to subcordate and ciliate on the margins, apices acute.

7-27 cm long, 4-24 cm wide, 1/4 - 1/3 as long as the plants, diffuse, usually exserted at anthesis, not breaking at the base of the peduncles to become a tumbleweed;

rachises glabrous or sparsely pilose basally;

primary branches spreading, secondary branches and pedicels confined to the distal 2/3 secondary branches diverging to appressed, with 1-4 spikelets;

pedicels 3-15 mm, spreading to appressed, scabrous or hirsute;

pulvini glabrous or pilose.

(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.

1.4-2.4 mm long, 0.5-0.7 mm wide, usually green, glabrous.

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

0.5-0.9 mm, usually less than 1/2 as long as the spikelets, 3-4-veined, truncate to acuminate;

upper glumes 1.6-2 mm, 7-veined, veins not prominent;

lower lemmas 1.6-1.9 mm, 7-9-veined, veins not prominent;

lower paleas absent;

lower florets sterile;

upper florets 1.5-1.7 mm long, about 0.4 mm wide, often dark brown, sometimes disarticulating, apices minutely papillose.

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.

= 18.

= 36.