Flora of North America species comparison

15-60 cm, erect or the bases decumbent, not branching above the base, terete or weakly compressed;

nodes terete, 0-1 exserted.

(15)30-80 cm, erect or the bases decumbent, terete or weakly compressed;

nodes terete, 1-3 exserted.

closed for about 1/2 their length, slightly compressed, distinctly keeled, glabrous, bases of basal sheaths glabrous, distal sheath lengths 4-60 times blade lengths;

collars of proximal leaves usually retrorsely scabrous or pubescent distally and about the throat;

ligules 0.5-4 mm, smooth or scabrous, apices truncate to acute;

innovation blades similar to the cauline blades;

cauline blades 1-4 mm wide, usually flat, sometimes slightly folded, smooth or sparsely scabrous, primarily over the veins, apices broadly prow-shaped, blades steeply reduced in length distally, flag leaf blades 0.2-3(6) cm.

closed for 1/2 - 9/10 their length, compressed, smooth, glabrous, bases of basal sheaths glabrous, distal sheath lengths 1-3 times blade lengths;

collars smooth, glabrous;

ligules 0.5-4 mm, smooth or sparsely scabrous, truncate to obtuse;

innovation blades similar to the cauline blades;

cauline blades 2-5 mm wide, flat, thin, smooth or sparsely scabrous mainly over the veins, apices broadly prow-shaped, middle and upper cauline blades subequal in length, flag leaf blades (2.5)4-7(11) cm long.

mainly extravaginal.

all or mostly extravaginal.

5-15 cm, erect or lax, pyramidal, open, sparse, with 20-80 spikelets, proximal internodes usually 3+ cm;

nodes usually with 2 branches;

branches (2)3-7(10) cm, spreading to reflexed, straight, angled, angles scabrous, with 2-8(10) spikelets.

(5)12-22 cm, usually narrowly pyramidal, open, sparse, with 20-70 spikelets, proximal internodes usually (3.5)4+ cm, with 2-3(4) branches per node;

branches 3-8 cm, spreading to eventually reflexed, terete or weakly angled, sparsely to moderately scabrous, with 3-12 spikelets.

5-8 mm, lengths to 3.5 times widths, laterally compressed, not sexually dimorphic;

florets 2-5;

rachilla internodes smooth.

5-9 mm, lengths to 3.5 times widths, laterally compressed, not sexually dimorphic;

florets 2-6;

rachilla internodes smooth, glabrous, distal internodes 1+ mm.

narrowly lanceolate to lanceolate, distinctly keeled;

lower glumes 1-3-veined;

calluses webbed, hairs over 1/3 the lemma length;

lemmas 3-6 mm, lanceolate, distinctly keeled, keels and marginal veins sparsely short- to long-villous, lateral veins moderately prominent, intercostal regions glabrous or the upper florets in the spikelets softly puberulent, margins glabrous, apices acute;

palea keels scabrous, softly puberulent at midlength;

anthers vestigial (0.1-0.2 mm) or 2-3.5 mm.

lanceolate, distinctly keeled;

lower glumes 1-3-veined;

calluses glabrous;

lemmas 3-6.5 mm, lanceolate, distinctly keeled, keels and marginal veins glabrous or short-villous to softly puberulent to 1/3 their length, lateral veins obscure, intercostal regions glabrous or sparsely hispidulous, rarely softly puberulent, smooth or sparsely finely scabrous, margins glabrous, apices acute;

palea keels scabrous, glabrous, intercostal regions glabrous;

anthers vestigial (0.1-0.2 mm) or (1.3)2-3.6 mm.

= 28.

= unknown.