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.

usually erect, not compressed.

not keeled;

ligules of hairs, or membranous and, usually, ciliate;

blades with vascular bundles separated by 2-6 radially arranged, tabular mesophyll cells and surrounded by a double sheath, cells of the inner sheath thick-walled, cells of the outer sheath with thinner cell walls and usually centripetal chloroplasts;

chloroplasts with well-developed grana.

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.

usually pyramidal, lax and diffuse, varying to contracted and condensed;

secondary branches usually present;

pedicels divergent to more or less appressed.

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

ellipsoid to lanceolate, 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.

1/5 - 4/5 the length of the spikelets, 1-11-veined;

upper glumes and lower lemmas (5)7-15-veined;

lower florets usually sterile;

upper florets smooth, shining;

upper paleas with compound or compound and simple papillae towards the apices, x = 9.

C4 NAD-me type.

= 18.