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.

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

nodes glabrous;

internodes glabrous.

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.

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.

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.

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

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

0.5-0.9 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.

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.

= 18.

= 20.