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.

7-25 cm.

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 1/7-1/4(1/3) their length, terete;

ligules of cauline leaves 1-3 mm, milky white, usually densely scabrous, sometimes smooth, ligules of the upper innovation leaves 0.5-2.5 mm;

innovation blades adaxially scabrous, hispidulous, or puberulent on and between the veins, lacking papillae on the long cells (at 100x);

cauline blades folded to involute, moderately thick, soft or moderately firm, apices narrowly prow-shaped, flag leaf blades 1-2 mm wide, adaxial surfaces with 5-9 well-spaced ribs.

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.

3-6 cm, erect, narrowly lanceoloid, contracted, moderately congested;

nodes with 1-2 branches;

branches to 1.5 cm, erect, slender, terete, sulcate or angled, smooth or the angles moderately scabrous;

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.

4.2-7 mm, laterally compressed, often strongly anthocyanic;

florets 2-4;

rachilla internodes 1-1.5 mm, smooth, sometimes 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.

lanceolate, distinctly keeled, keels smooth;

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

upper glumes frequently exceeding the lowest lemmas, 3-5-veined, exceeded by the upper lemmas;

calluses glabrous;

lemmas 4.1-5.8 mm, narrowly lanceolate, distinctly keeled, thin, glabrous, apices acute;

palea keels scabrous;

anthers 0.8-1.2(1.7) mm, infrequently aborted late in development.

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

= unknown.