Flora of North America species comparison

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

nodes terete, 0-1 exserted.

15-70 cm, sometimes stout, erect or the bases decumbent, terete or weakly compressed;

nodes terete, 0-1 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 or scabrous, glabrous or occasionally retrorsely pubescent, bases of basal sheaths glabrous, distal sheath lengths usually (5)9+ times blade lengths;

collars smooth or scabrous, glabrous or hispidulous;

ligules 0.2-18 mm, smooth or scabrous, decurrent or not, apices truncate to acuminate, ciliolate or glabrous;

innovation blades usually moderately to densely scabrous or hispidulous on and between the veins, infrequently nearly smooth and glabrous;

cauline blades strongly reduced in length distally, (0.5)1-3(4) mm wide, usually involute, moderately thick and firm, infrequently moderately thin, abaxial surfaces usually smooth, infrequently scabrous, apices narrowly prow-shaped, steeply reduced in length distally along the culm, flag leaf blades often absent or very reduced, sometimes to 1(3) cm.

intra- and extravaginal.

mainly intravaginal, usually some extravaginal.

(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.

2-12(30) cm, erect, contracted, narrowly lanceoloid to ovoid, congested, frequently with 100+ spikelets;

nodes with 1-2 branches;

branches 1-8 cm, erect, terete to weakly angled, smooth or scabrous, with 3-15(25) 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)4-8(12) mm, lengths to 3 times widths, broadly lanceolate to ovate, laterally compressed, not sexually dimorphic;

florets 2-7(13);

rachilla internodes 0.8-1.3 mm, smooth, glabrous or hairy, hairs to 0.3 mm.

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.

lanceolate, distinctly keeled;

lower glumes 1-3-veined, distinctly shorter than the lowest lemmas;

calluses glabrous;

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

palea keels scabrous, sometimes softly puberulent or long-villous at midlength, hairs to 0.4+ mm;

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

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

= 28+11, 56, 56-58, 58-64.