Flora of North America species comparison

10-60(70) cm tall, 0.5-1.8 mm thick, erect or the bases decumbent, terete or weakly compressed;

nodes terete, 0-2 exserted.

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

nodes terete, 1-2 exserted.

closed for 1/4-3/4 their length, terete, smooth or scabrous, glabrous, bases of basal sheaths glabrous, distal sheath lengths 1.6-10 times blade lengths;

collars smooth or scabrous, glabrous;

ligules of cauline leaves 1-3(6) mm, smooth or scabrous, truncate to acute, ligules of the innovation leaves 0.2-0.5(2.5) mm, scabrous, usually truncate;

innovation blades sometimes distinctly different from the cauline blades, 0.5-2 mm wide, involute, moderately thick, moderately firm, adaxial surfaces usually densely scabrous or hispidulous to softly puberulent, infrequently nearly smooth and glabrous;

cauline blades subequal or the midcauline blades longest or the blades gradually reduced in length distally, 0.5-3 mm wide, flat, folded, or involute, usually thin, usually withering, abaxial surfaces smooth or scabrous, apices narrowly to broadly prow-shaped, flag leaf blades 0.5-5(6) cm.

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.

intravaginal or intra- and extravaginal.

mainly extravaginal.

2-10(12) cm, usually erect, contracted or loosely contracted, narrowly lanceoloid to ovoid, congested or moderately congested, with 10-100 spikelets and 1-3(5) branches per node;

branches 0.5-4(5) cm, erect or steeply ascending, fairly straight, slender to stout, terete to angled, smooth or scabrous, with 1-15 spikelets.

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)4-10 mm, lengths to 3 times widths, broadly lanceolate to narrowly ovate, laterally compressed, not sexually dimorphic;

florets 2-6;

rachilla internodes 0.5-1.2 mm, smooth or scabrous.

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.

lanceolate, distinctly keeled;

lower glumes 3-veined, distinctly shorter than the lowest lemmas;

calluses glabrous or diffusely webbed, hairs less than 1/4 the lemma length;

lemmas (3)4-7 mm, lanceolate to broadly lanceolate, distinctly keeled, membranous to thinly membranous, smooth or sparsely to densely scabrous, glabrous or the keels and/or marginal veins puberulent proximally, lateral veins obscure to prominent, margins glabrous, apices acute;

palea keels scabrous, intercostal regions glabrous;

anthers vestigial (0.1-0.2 mm), aborted late in development, or 2-3.5 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+11, 56, 56+11, 59, ca. 70.

= 28, 28+1.