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.

5-40 cm, erect or ascending, frequently decumbent, terete, with 0-2 exserted nodes.

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 1/10(1/5) their length, terete, smooth, glabrous, bases of basal sheaths glabrous, distal sheath lengths 1-4 times widths;

ligules 2-6 mm, smooth or sparsely scabrous, obtuse to acute;

innovation blades usually 1-1.5 mm wide, thin, soon withering, and distinctly narrower than the cauline blades, infrequently wider, flat, and a bit fleshy as in the cauline blades, or involute;

cauline blades gradually reduced in length distally, 2-5 mm wide, flat or folded, soft, thin and soon withering or moderately thick and somewhat fleshy and retaining their form, smooth, apices narrowly to broadly prow-shaped.

mainly extravaginal.

all or mainly intravaginal.

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.

3-7 cm, erect, nearly cylindrical, contracted, congested, with (20)30-80(120) spikelets;

nodes with 3-7 branches;

branches 0.5-1.5(4.5) cm, erect, usually angled, infrequently terete or sulcate, angles usually moderately to densely scabrous, infrequently smooth with dense papillae and weak-angled, with 2-10 spikelets in the proximal 2/3;

pedicels shorter than the spikelets.

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

florets 2-5;

rachilla internodes smooth.

4.5-7 mm, lengths to 3.5 times widths, lanceolate to narrowly ovate, drab;

florets 3-5;

rachilla internodes usually shorter than 1 mm, smooth.

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, slightly unequal, distinctly keeled, keels papillate or scabrous;

lower glumes 3-veined;

calluses glabrous or with a crown of hairs, hairs 0.1-0.2 mm;

lemmas 3-4.5 mm, lanceolate, distinctly keeled, glabrous or the keels and marginal veins short-villous to midlength, intercostal regions sparsely puberulent near the base, margins glabrous, apices acute;

palea keels scabrous, sometimes softly puberulent at midlength;

anthers 1.5-3 mm.

= 28.

= 42, 84.