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.

25-50 cm, bases decumbent, with 1-2 well-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 1/2-3/4 their length, distal sheath lengths 1.6-5 times blade lengths;

innovation blades mostly 1-2 mm wide;

cauline blades more than 1.5 mm wide, flat or folded, apices usually broadly prow-shaped, flag leaf blades 3-6 cm.

intravaginal or intra- and extravaginal.

mostly 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.

usually 4-7 cm, slightly lax, ovate, loosely contracted, with 13-50 spikelets;

nodes with 1-3 branches;

branches 1-3(4) cm, moderately stout, smooth to moderately scabrous, with 1-8 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.

7-10 mm.

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.

of proximal lemmas usually sparsely and shortly webbed, hairs less than 1/4 the lemma length, sometimes glabrous, those of the distal lemmas glabrous;

lemmas 4-7 mm, usually the keels and marginal veins of some proximal lemmas sparsely puberulent near the base, sometimes glabrous, distal lemmas glabrous;

anthers usually aborted late in development.

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

= 28+11, 56.