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.

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

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 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.

intravaginal or intra- and extravaginal.

all or mainly intravaginal.

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.

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.

(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.

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

florets 3-5;

rachilla internodes usually shorter than 1 mm, smooth.

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.

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, 28+11, 56, 56+11, 59, ca. 70.

= 42, 84.