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.

7-30 (35) cm tall, 0.4-0.9 mm thick, slender, erect or the bases decumbent, terete or weakly compressed;

nodes terete, 0-1 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 1/3-2/3 their length, terete, smooth, glabrous, bases of basal sheaths glabrous, distal sheath lengths (1)1.4-4.5 times blade lengths;

collars smooth, glabrous;

ligules 0.5-1.5(2.2) mm, scabrous, truncate to acute;

innovation blades adaxially moderately to densely scabrous or hispidulous on and between the veins;

cauline blades slightly reduced in length distally, 0.5-1(1.5) mm wide, involute, thin to moderately thick, usually filiform, soft, abaxial surfaces smooth, adaxial surfaces sparsely scabrous on and between the veins, apices narrowly prow-shaped, flag leaf blades (0.5)1-5 cm.

mainly extravaginal.

mainly intravaginal, some 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.

1-5(7) cm, erect, ovoid, fairly tightly to loosely contracted, congested or moderately congested, with fewer than 50 spikelets;

nodes with 1-2 branches;

branches 0.5-3 cm, erect to ascending, slightly lax, terete or angled, angles sparsely to densely scabrous, with 2-12 spikelets.

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

florets 2-5;

rachilla internodes smooth.

3-6(8) mm, lengths to 3 times widths, laterally compressed, compact, not sexually dimorphic;

florets 2-5;

rachilla internodes 0.8-1.1 mm, usually not readily visible from the sides, glabrous or sparsely puberulent.

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.

slightly unequal, distinctly keeled, keels smooth or scabrous;

lower glumes 2-4 mm, 1-3-veined, about 2/3 the length of the adjacent lemmas;

upper glumes 2.9-5 mm;

calluses usually diffusely webbed, hairs 1-2 mm, infrequently glabrous;

lemmas 2.5-4(4.5) mm, lanceolate, distinctly keeled, moderately to densely finely scabrous, glabrous throughout or the keels and sometimes the marginal veins sparsely puberulent proximally, margins narrowly scarious, glabrous, apices acute;

paleas subequal to the lemmas, keels scabrous, intercostal regions glabrous;

anthers vestigial (0.1-0.2 mm) or 1.5-2 mm.

= 28.

= 42.