Flora of North America species comparison

5-15(20) cm, slender, leafless above the basal tuft.

(25)32-125 cm, erect or the bases decumbent, not branching above the base, terete or weakly compressed;

nodes terete or slightly compressed, 1-2(3) exserted.

closed for 1/10 – 1/4 their length, terete;

ligules 0.4-5.5 mm, milky white to hyaline, smooth or scabrous, apices truncate to acute;

blades 0.8-1.5(2) mm wide, involute, moderately thick, soft, apices narrowly prow-shaped.

closed for (2/5)1/2 – 9/10 their length, compressed, distinctly keeled, keels winged, wing to 0.5 mm wide, smooth or sparsely to infrequently densely scabrous, glabrous or infrequently retrorsely pubescent, bases of basal sheaths glabrous, distal sheath lengths 0.7-1.6 times blade lengths;

collars with vestiture similar to the sheaths;

ligules 2-4.5 mm, smooth or scabrous, glabrous or softly puberulent, obtuse to acute;

innovation blades similar to the cauline blades;

cauline blades (1.5)2-5.5 mm wide, flat, lax, smooth or sparsely scabrous mainly over the veins, apices broadly prow-shaped, flag leaf blades 6-20 cm.

all or mainly intravaginal.

mainly extravaginal.

1.5-5 cm, erect, lanceoloid to ovoid, contracted, congested;

nodes with 1-3 branches;

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

pedicels usually shorter than the spikelets.

(8)13-29 cm, erect, usually narrowly pyramidal, open, sparse, with 30-100 spikelets, proximal internodes usually 4+ cm, with (1)2-4(5) branches per node;

branches 2.5-18 cm, spreading to eventually reflexed, fairly flexuous, terete to weakly angled, sparsely to moderately scabrous, with 3-34 spikelets.

4-6.5 mm, laterally compressed, rarely bulbiferous, frequently strongly anthocyanic;

florets 2-5, rarely bulb-forming;

rachilla internodes usually shorter than 1 mm, smooth or scabrous.

3-8 mm, lengths 3.5 times widths, laterally compressed, not sexually dimorphic;

florets 2-8;

rachilla internodes 1+ mm, smooth, glabrous.

subequal to slightly longer than the adjacent lemmas, lanceolate to broadly lanceolate, distinctly keeled, keels smooth;

lower glumes (1)3-veined, lateral veins often faint and short;

upper glumes exceeding or exceeded by the upper florets;

calluses glabrous or webbed;

lemmas 3-4.6 mm, lanceolate to broadly lanceolate, distinctly keeled, thin, keels and marginal veins usually short- to long-villous, hairs extending along 3/4 - 5/6 of the keel, infrequently glabrous, intercostal regions glabrous or softly puberulent to short-villous, apices acute;

palea keels scabrous, often short-villous to softly puberulent at midlength, sometimes glabrous;

anthers 0.2-1.2(1.8) mm.

narrowly lanceolate, distinctly keeled;

lower glumes 1.6-3.5 mm, 1(3)-veined, 1/2-1/3 as long as the adjacent lemmas;

upper glumes 2.2-4.9 mm;

calluses webbed, hairs over 1/2 the lemma length;

lemmas 2.6-5 mm, lanceolate, distinctly keeled, keels and marginal veins long-villous, extending 1/2 - 2/3 the keel length, 1/3-1/2 the marginal vein length, lateral veins sometimes short-villous, the lateral veins obscure to moderately prominent, intercostal regions usually sparsely softly puberulent, margins glabrous, apices acute;

palea keels scabrous, rarely softly puberulent at midlength;

anthers vestigial (0.1-0.2 mm) or (1.3)2-3 mm.

= 42.

= 28, 28+1.