Flora of North America species comparison

15-80 cm, erect or the bases decumbent, terete or weakly compressed;

nodes terete, 0-1 exserted.

10-55 cm, erect or the bases decumbent, terete or weakly compressed;

nodes terete, not exserted.

closed for 1/10 – 1/5(1/4) their length, terete, smooth or sparsely scabrous, glabrous, bases of basal sheaths glabrous, distal sheath lengths (1.2)1.5-9(20) times blade lengths;

ligules (1)1.5-4(5) mm, smooth or sparsely to moderately scabrous, apices obtuse to acute;

blades strongly to gradually reduced in length distally, 1.5-5 mm wide, flat and moderately thin to folded and moderately thick and firm, abaxial surfaces smooth, adaxial surfaces smooth or sparsely to moderately scabrous, primarily over the veins, apices narrowly prow-shaped, flag leaf blades (0.4)1-7(10) cm.

closed for about 1/3 their length, terete, smooth, glabrous, bases of basal sheaths glabrous, distal sheath lengths 1.5-7.5 times blade lengths;

collars smooth, glabrous;

ligules 1-2 mm, smooth or sparsely scabrous, apices truncate to obtuse;

innovation blades similar to the cauline blades, adaxial surfaces nearly smooth, glabrous on and between the veins;

cauline blades fairly strongly reduced in length distally, 1-3 mm wide, folded to involute, moderately thick, moderately firm, abaxial surfaces smooth, apices narrowly prow-shaped, flag leaf blades 1-5.5 cm.

intra- and extravaginal.

extra- and intravaginal.

(2.5)4-12(18) cm, erect, usually narrowly lanceoloid, contracted, sometimes interrupted, infrequently loosely contracted, usually congested, with 25-100 spikelets;

nodes with 1-5 branches;

branches 1-9 cm, erect to infrequently ascending, rarely spreading, terete to weakly angled, smooth or the angles sparsely to moderately scabrous, with 3-24 spikelets.

3-7 cm, erect, lanceoloid to ovoid, congested, with 20-70 spikelets;

nodes with 1-2 branches;

branches 0.5-3 cm, erect, terete, usually smooth, infrequently sparsely scabrous distally, with 3-12 spikelets.

3.2-7 mm, lengths to 3.5(3.8) times widths, laterally compressed;

florets 2-7;

rachilla internodes smooth, sometimes sparsely puberulent.

3.5-5.5 mm, lengths to 3 times widths, laterally compressed, very compact, not sexually dimorphic;

florets 2-5;

rachilla internodes about 0.5 mm, smooth, glabrous.

lanceolate, distinctly keeled, smooth or sparsely scabrous;

lower glumes 3-veined;

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

lemmas 2.5-4.5 mm, lanceolate to narrowly lanceolate, distinctly to weakly keeled, keels and marginal veins short- to long-villous, lateral veins moderately prominent, glabrous or puberulent, intercostal regions usually glabrous, infrequently hairy, hairs to 0.3 mm, margins glabrous, apices acute or blunt;

palea keels scabrous, glabrous or short-villous at midlength, intercostal regions usually glabrous, sometimes puberulent to short-villous;

anthers 1.3-2.2 mm.

broadly lanceolate, distinctly shorter than the adjacent lemmas, distinctly keeled, keels smooth or sparsely scabrous;

lower glumes 3-veined;

calluses glabrous;

lemmas 2.5-3.5 mm, lanceolate, usually purplish, distinctly keeled, glabrous, smooth, margins glabrous, apices acute;

palea keels scabrous, intercostal regions glabrous;

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

= 56, 56+1, 56-58, 63, 64, 70, 76, 84, ca. 90, 95+-5, 100, 103.

= 28.