Flora of North America species comparison

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

nodes terete, 0-1 exserted.

5-35 cm tall, 0.5-0.7 mm thick, erect or the bases decumbent, with 0-1 exserted nodes.

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 2/5 – 4/5 their length, terete, smooth and glabrous, bases of basal sheaths glabrous;

collars smooth, glabrous;

ligules (1)2-4 mm, colorless, transparent, smooth, margins decurrent or not, apices truncate to acute, ligules of innovation and cauline leaves alike;

innovation blades smooth or sparsely scabrous abaxially;

cauline blades 0.5-1 mm wide, flat, folded, or involute, thin, lax, filiform, usually soon withering, both surfaces smooth or sparsely scabrous, apices narrowly prow-shaped.

intra- and extravaginal.

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.

1-5(8) cm, erect to lax, lanceoloid to ovoid or pyramidal, contracted to open, sparse, with (1)6-17(22) spikelets;

nodes with 1-2 branches;

branches 1-4 cm, erect to spreading, slender, terete, smooth or sparsely to rarely moderately densely scabrous, with 1-2(3) spikelets.

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

florets 2-7;

rachilla internodes smooth, sometimes sparsely puberulent.

4-8 mm, lengths to 3 times widths, broadly lanceolate to broadly ovate, laterally compressed, not sexually dimorphic;

florets 2-8;

rachilla internodes 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.

thin, somewhat lustrous, distinctly keeled;

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

calluses glabrous;

lemmas 3.5-7 mm, lanceolate, distinctly keeled, thinly membranous, smooth or scabrous, glabrous, lateral veins moderately prominent to prominent, margins glabrous, apices acute to truncate and erose;

palea keels smooth or scabrous, glabrous or pectinately ciliate;

anthers vestigial (0.1-0.2 mm) or 1.3-3 mm.

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

= unknown.