Flora of North America species comparison

23-86 cm tall, 0.8-1.8 mm thick, bases often decumbent.

20-65 cm, erect or the bases decumbent, terete or weakly compressed;

nodes terete, 1-2 exserted.

closed for 1/3 – 1/2 their length;

ligules 0.2-1.9(2.5) mm, smooth or obtuse;

blades (0.5)1-4 mm wide, flat or folded, thin.

closed for 2/3 – 9/10 their length, terete to slightly compressed, smooth or sparsely scabrous, sometimes hairy, hairs about 0.15 mm, bases of basal sheaths glabrous, distal sheath lengths (0.7)1-2.2(2.8) times blade lengths;

collars of proximal leaves usually hairy on and near the margins, marginal hairs longer than those of the sheaths;

ligules 0.5-1.5 mm, smooth or scabrous, hairy, hairs about 0.15 mm, truncate to obtuse, those of the lower culm and innovation leaves 0.5-1 mm, scabrous or softly puberulent, truncate;

innovation blades similar to or longer than the cauline blades;

cauline blades 2-4.5 mm wide, usually flat, lax, adaxial surfaces smooth or sparsely scabrous, particularly over the veins, apices broadly prow-shaped, blades gradually reduced in length distally or the middle blades longest, flag leaf blades 3-8 cm long.

mainly pseudointravaginal.

mainly extravaginal.

(5)8-20 cm, erect or lax, broadly pyramidal at maturity, open, sparse, lower axils sometimes sparsely pubescent;

nodes with 1-2(4) branches;

branches 5-12 cm, spreading to reflexed, straight, angled, angles scabrous, with 3-8 spikelets in the distal 1/4-1/3.

8-15 cm, erect or lax, ovoid to pyramidal, open or loosely contracted, sparse, with 25-80 spikelets, proximal internodes 1.8-3.5 cm;

nodes with 3-5 branches;

branches 2.5-8 cm, ascending to spreading, lax, terete to weakly angled, moderately scabrous, with 2-8 spikelets.

3-8.2 mm, laterally compressed;

florets 2-4(6);

rachilla internodes smooth, sparsely softly puberulent.

4-7 mm, lengths to 3.5 times widths, laterally compressed, not sexually dimorphic;

florets 3-8;

rachilla internodes smooth or scabrous, glabrous or sparsely hispidulous.

distinctly shorter than the adjacent lemmas, distinctly keeled, keels scabrous;

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

upper glumes lanceolate to broadly lanceolate;

calluses usually glabrous, rarely sparsely and shortly webbed;

lemmas (2.8)3-4.6 mm, lanceolate, distinctly keeled, keels and marginal veins short- to long-villous, hairs extending up 3/4 of the keel, lateral veins prominent, intercostal regions softly puberulent, smooth, apices obtuse, blunt;

palea keels softly puberulent to short-villous for much of their length, apices scabrous;

anthers 1-1.4(2.6) mm.

2/3 – 4/5 as long as the adjacent lemmas, lanceolate, distinctly keeled;

lower glumes 1-3(5)-veined;

calluses usually glabrous, rarely minutely webbed;

lemmas 3-4.5 mm, lanceolate, distinctly keeled, keels and marginal veins usually glabrous, infrequently sparsely softly puberulent to short-villous, intercostal regions glabrous or hispidulous, smooth or finely scabrous, margins glabrous, apices acute;

paleas scabrous over the keels, intercostal regions glabrous;

anthers usually 2.5-4 mm, sometimes vestigial (0.1-0.2 mm).

= 28.

= 28, 28+1.