Flora of North America species comparison

30-120 cm, bases often decumbent.

20-40(75) cm, erect or the bases decumbent, not branching above the base, terete or weakly compressed;

nodes terete, proximal nodes usually not exserted.

closed for (1/20) 1/2-7/8 their length, terete, throats frequently ciliate near the point of fusion;

ligules 0.5-2.7 mm, smooth or sparsely scabrous, truncate to obtuse;

blades 0.7-5 mm wide, flat, thin, lax.

closed for 2/5 – 1/2 their length, terete, glabrous, smooth or slightly scabrous, bases of basal sheaths glabrous, distal sheath lengths (1)1.2-3.5 times blade lengths;

collars smooth, glabrous;

ligules 1.5-4(6) mm, smooth, apices obtuse to acute, not ciliate;

blades 1-3.5(5) mm wide, folded or flat, innovation shoot blades involute, soft, abaxial surfaces glabrous, adaxial surfaces smooth or sparsely scabrous, frequently sparsely hairy with 0.2-0.8 mm hairs, slender, erect to appressed, curving, sinuous or straight, apices narrowly prow-shaped, cauline blades subequal, flag leaf blades 1.5-8 cm.

mainly pseudointravaginal.

mainly extravaginal.

(6.7)9-20 cm, open, narrowly conical at maturity;

nodes with (2)3-10 branches per node;

branches (2)3-7 cm, spreading to eventually reflexed, straight, angled, angles several, densely scabrous, with 1-11 spikelets.

5-9(17) cm, narrowly lanceoloid to narrowly pyramidal, loosely contacted to open, sparse, with 25-60 spikelets and 2-5 branches per node;

branches 1-3 cm, ascending to spreading, slightly flexuous to fairly straight, terete, smooth or sparsely scabrous, usually with 1-5 spikelets per branch, the spikelets moderately crowded in the distal 1/2.

2.5-4.4 mm, laterally compressed;

florets 2-3(4);

rachilla internodes longer than (1)1.2 mm, smooth, glabrous.

4-6.5(8) mm, lengths to 3 times widths, laterally compressed;

florets 2-4(6);

rachilla internodes shorter than 1 mm, smooth, usually glabrous, rarely with a few hairs.

distinctly keeled, keels scabrous;

lower glumes 1(3)-veined;

upper glumes shorter than or subequal to the lowest lemmas;

calluses webbed;

lemmas 2.1-3.1 mm, broadly lanceolate, distinctly keeled, keels and marginal veins short-villous, extending to near the apices on the keels, lateral veins prominent, softly puberulent to short-villous, intercostal regions usually sparsely softly puberulent, smooth, apices obtuse to acute;

palea keels softly puberulent at midlength, apices finely scabrous;

anthers 1-1.8 mm.

unequal to subequal, usually distinctly shorter than the adjacent lemmas, lanceolate, distinctly keeled, keels smooth to sparsely scabrous;

lower glumes 2.8-3.5 mm, narrowly lanceolate, (1)3-veined;

upper glumes 4-4.5(5) mm, distinctly shorter than to nearly equaling the lowest lemmas;

calluses dorsally webbed, webs copious, hairs at least 1/2 times the lemma length, sometimes secondary webs present under the marginal veins;

lemmas 3.7-4.5(5) mm, lanceolate, usually strongly purple, distinctly keeled, keels, lateral veins, and marginal veins copiously hairy, hairs cottony, lateral veins prominent, less hairy, intercostal regions glabrous, usually smooth or finely muriculate, sometimes sparsely scabrous distally, margins narrowly hyaline, glabrous, apices acute;

palea keels sparsely scabrous, long-villous at midlength, intercostal regions narrow, glabrous;

anthers 1.8-2.5 mm.

= 28.

= 56, ca. 70.