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.

20-80 cm, erect or the bases decumbent.

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.

usually closed for about 1/6 their length;

ligules 1-4 mm, smooth or sparsely scabrous, apices obtuse to acute;

innovation blades 0.5-2 mm wide;

cauline blades 0.5-5 mm wide, flat, folded, abaxial surfaces smooth or 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.

5-15 cm, erect, usually contracted, sometimes interrupted;

branches shorter than 4 cm, erect, angles somewhat scabrous.

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

florets 2-5;

rachilla internodes smooth.

4-7 mm, weakly laterally compressed;

florets 2-5;

rachilla internodes smooth.

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.

glumes 3-veined;

calluses glabrous or webbed, hairs to 1/4 the lemma length;

lemmas 2.5-4.5 mm, narrowly lanceolate, distinctly to weakly keeled, glabrous throughout or the keels and marginal veins sparsely long-villous, apices acute;

palea keels scabrous;

anthers aborted late in development or 1.3-2.2 mm.

= 28.

= 64.