Flora of North America species comparison

15-60 cm, wiry, bases usually geniculate, strongly compressed;

nodes strongly compressed, some proximal nodes usually exserted.

(25)32-125 cm, erect or the bases decumbent, not branching above the base, terete or weakly compressed;

nodes terete or slightly compressed, 1-2(3) exserted.

closed for 1/10 – 1/5 their length, distinctly compressed, bases of basal sheaths glabrous;

ligules 1-3 mm, moderately to densely scabrous, ciliolate, apices obtuse;

blades 1.5-4 mm wide, flat, cauline blades subequal.

closed for (2/5)1/2 – 9/10 their length, compressed, distinctly keeled, keels winged, wing to 0.5 mm wide, smooth or sparsely to infrequently densely scabrous, glabrous or infrequently retrorsely pubescent, bases of basal sheaths glabrous, distal sheath lengths 0.7-1.6 times blade lengths;

collars with vestiture similar to the sheaths;

ligules 2-4.5 mm, smooth or scabrous, glabrous or softly puberulent, obtuse to acute;

innovation blades similar to the cauline blades;

cauline blades (1.5)2-5.5 mm wide, flat, lax, smooth or sparsely scabrous mainly over the veins, apices broadly prow-shaped, flag leaf blades 6-20 cm.

mainly extravaginal.

2-10 cm, generally 1/6 - 1/3 as wide as long, erect, linear, lanceoloid to ovoid, often interrupted, sparse to congested, with 15-80 spikelets and mostly with 1-3 branches per node;

branches 0.5-3 cm, erect to ascending, or infrequently spreading, angles densely scabrous, at least in part, with 1-15 spikelets.

(8)13-29 cm, erect, usually narrowly pyramidal, open, sparse, with 30-100 spikelets, proximal internodes usually 4+ cm, with (1)2-4(5) branches per node;

branches 2.5-18 cm, spreading to eventually reflexed, fairly flexuous, terete to weakly angled, sparsely to moderately scabrous, with 3-34 spikelets.

(2.3)3.5-7 mm, laterally compressed;

florets 3-7;

rachilla internodes usually shorter than 1 mm, smooth to muriculate.

3-8 mm, lengths 3.5 times widths, laterally compressed, not sexually dimorphic;

florets 2-8;

rachilla internodes 1+ mm, smooth, glabrous.

distinctly keeled;

lower glumes 3-veined;

calluses usually webbed, sometimes glabrous;

lemmas 2.3-3.5 mm, lanceolate, distinctly keeled, keels and marginal veins short-villous, intercostal regions glabrous, lateral veins obscure, margins glabrous, apices acute;

paleas scabrous over the keels;

anthers 1.3-1.8 mm.

narrowly lanceolate, distinctly keeled;

lower glumes 1.6-3.5 mm, 1(3)-veined, 1/2-1/3 as long as the adjacent lemmas;

upper glumes 2.2-4.9 mm;

calluses webbed, hairs over 1/2 the lemma length;

lemmas 2.6-5 mm, lanceolate, distinctly keeled, keels and marginal veins long-villous, extending 1/2 - 2/3 the keel length, 1/3-1/2 the marginal vein length, lateral veins sometimes short-villous, the lateral veins obscure to moderately prominent, intercostal regions usually sparsely softly puberulent, margins glabrous, apices acute;

palea keels scabrous, rarely softly puberulent at midlength;

anthers vestigial (0.1-0.2 mm) or (1.3)2-3 mm.

= 35, 42, 49, 50, 56, 84.

= 28, 28+1.