Flora of North America species comparison

25-90 cm.

(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 1/2 - 3/4 their length, smooth or sparsely scabrous, margins not ciliate;

ligules 0.3-2.1 mm, smooth or sparsely scabrous, truncate to obtuse, ciliolate;

blades 0.6-3.5 mm wide, flat.

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 pseudointravaginal.

mainly extravaginal.

7.5-15(18) cm, lax, pyramidal, open, sparse;

nodes with 1-3(5) branches;

branches 3-8 cm, ascending, straight to spreading, angled, angles prominent, scabrous.

(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.

4-6.5 mm, laterally compressed;

florets 2-5;

rachilla internodes to 1 mm, smooth, glabrous.

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

florets 2-8;

rachilla internodes 1+ mm, smooth, glabrous.

1/2-1/3 the length of the adjacent lemmas, distinctly keeled, keels scabrous;

lower glumes subulate to narrowly lanceolate, (1)3-veined;

upper glumes shorter than or subequal to the lowest lemmas;

calluses webbed;

lemmas (2.5)3.2-4.7 mm, lanceolate, green, distinctly keeled, keels and marginal veins long-villous, hairs extending up almost the whole keel length, lateral veins prominent, intercostal regions smooth, minutely bumpy, usually glabrous, rarely sparsely softly puberulent, apices acute, blunt, or pointed, white, not bronze;

palea keels softly puberulent at midlength, apices scabrous;

anthers (0.5)0.8-1.2(1.5) 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.

= 28.

= 28, 28+1.