Flora of North America species comparison

15-60 cm, erect or the bases decumbent, not branching above the base, terete or weakly compressed;

nodes terete, 0-1 exserted.

5-30(40) cm tall, 0.3-0.7 mm thick, erect or the bases geniculate;

nodes terete, usually 1 exserted.

closed for about 1/2 their length, slightly compressed, distinctly keeled, glabrous, bases of basal sheaths glabrous, distal sheath lengths 4-60 times blade lengths;

collars of proximal leaves usually retrorsely scabrous or pubescent distally and about the throat;

ligules 0.5-4 mm, smooth or scabrous, apices truncate to acute;

innovation blades similar to the cauline blades;

cauline blades 1-4 mm wide, usually flat, sometimes slightly folded, smooth or sparsely scabrous, primarily over the veins, apices broadly prow-shaped, blades steeply reduced in length distally, flag leaf blades 0.2-3(6) cm.

closed for 1/10 – 1/2 their length, terete or weakly compressed, smooth;

ligules 0.7-5 mm, decurrent, truncate to acute;

blades of innovations and culms similar, 2-5(8) cm long, 0.6-2.8 mm wide, flat or folded, thin, soft, smooth, margins scabrous, apices narrowly prow-shaped.

mainly extravaginal.

5-15 cm, erect or lax, pyramidal, open, sparse, with 20-80 spikelets, proximal internodes usually 3+ cm;

nodes usually with 2 branches;

branches (2)3-7(10) cm, spreading to reflexed, straight, angled, angles scabrous, with 2-8(10) spikelets.

2-9.6 cm, erect, eventually open, moderately to densely congested, with 1-4(7) branches per node;

branches eventually ascending to spreading, rarely reflexed, terete, smooth or sparsely scabrous, spikelet-bearing to near the base or middle.

5-8 mm, lengths to 3.5 times widths, laterally compressed, not sexually dimorphic;

florets 2-5;

rachilla internodes smooth.

(2)2.4-4.5 mm, laterally compressed;

florets (1)2-6;

rachilla internodes usually shorter than 0.7 mm, smooth or scabrous, glabrous.

narrowly lanceolate to lanceolate, distinctly keeled;

lower glumes 1-3-veined;

calluses webbed, hairs over 1/3 the lemma length;

lemmas 3-6 mm, lanceolate, distinctly keeled, keels and marginal veins sparsely short- to long-villous, lateral veins moderately prominent, intercostal regions glabrous or the upper florets in the spikelets softly puberulent, margins glabrous, apices acute;

palea keels scabrous, softly puberulent at midlength;

anthers vestigial (0.1-0.2 mm) or 2-3.5 mm.

subequal, about 3/4 as long as to subequal to the adjacent lemmas, lanceolate, thin, distinctly keeled, keels scabrous;

lower glumes 1-3-veined;

calluses webbed;

lemmas 1.9-3 mm, broadly lanceolate, distinctly keeled, smooth, keels and marginal veins short- to long-villous, hairs on the keels extending to near the apices, lateral veins obscure, usually softly puberulent, intercostal regions usually sparsely softly puberulent, apices obtuse to acute;

palea keels softly puberulent to long-villous at midlength, scabrous near the apices;

anthers 1, 0.1-0.2(0.3) mm.

= 28.

= unknown.