Flora of North America species comparison

20-85 cm, erect, terete or weakly compressed;

nodes terete, 0-1 exserted.

10-50 cm, erect or the bases decumbent, terete or weakly compressed;

nodes terete, 0-1 exserted.

closed firmly for 1/7-1/3 their length, sometimes for a longer distance by a hyaline membrane, terete, smooth, glabrous, bases of basal sheaths glabrous;

ligules 1-4 mm, smooth or scabrous;

innovation blades 10-35 cm long, 1-3.5 mm wide;

cauline blades 2-25 cm long, 1.5-4.5 mm wide, flat or folded, lax, both surfaces smooth or sparsely finely scabrous, glabrous, apices narrowly to broadly prow-shaped.

closed for 1/3 – 7/8 their length, terete to slightly compressed, smooth, glabrous, bases of basal sheaths glabrous, distal sheath lengths (1.15)1.5-4.6(6.6) times blade lengths;

collars smooth, glabrous;

ligules 0.5-2(2.5) mm, smooth, truncate to obtuse;

innovation blades similar to the cauline blades;

cauline blades gradually reduced in length distally, 2-5 mm wide, flat or folded, smooth or the adaxial surfaces sparsely scabrous, primarily over the veins, apices broadly prow-shaped, flag leaf blades 0.7-6 cm.

intra- and extravaginal.

all or mainly extravaginal.

3-12(18) cm, erect, narrowly cylindrical, often interrupted or lobed, congested, with (70)100-200 spikelets;

nodes with (2)3-7(9) branches;

branches 1-3(5) cm, erect to slightly ascending, terete or weakly angled, sparsely to densely coarsely scabrous, with 8-30 spikelets.

2-9 cm, erect, lanceoloid to ovoid, tightly to loosely contracted, with 15-35 spikelets, proximal internodes shorter than 2 cm;

nodes with 1-2 branches;

branches 0.9-3.2 cm, erect to ascending or slightly spreading, terete, smooth or sparsely scabrous, with 1-4 spikelets.

4-8(10) mm, sexually dimorphic, laterally compressed, pistillate spikelets larger, with fewer florets and more pubescence than the staminate spikelets;

florets 2-10;

rachilla internodes smooth.

6-12 mm, lengths to 3 times widths, laterally compressed, not sexually dimorphic;

florets 2-7;

rachilla internodes 0.8-1.5 mm, smooth or sparsely scabrous, glabrous.

unequal, distinctly keeled, keels and lateral veins scabrous;

lower glumes 1-3-veined.

3/5- 4/5 as long as the adjacent lemmas, distinctly keeled;

lower glumes 3-veined;

calluses of at least some proximal florets sparsely webbed, with 1-2 mm hairs, others glabrous, rarely all glabrous;

lemmas 5-7 mm, lanceolate, 5-7-veined, distinctly keeled, smooth or sparsely finely scabrous, glabrous throughout or the keels and marginal veins sparsely softly puberulent over the proximal 1/4, lateral veins moderately prominent, intercostal regions glabrous, margins glabrous, apices acute;

palea keels sparsely scabrous, intercostal regions glabrous;

anthers vestigial (0.1-0.2 mm), aborted late in development, or 1.8-3.7 mm.

calluses copiously 3-webbed, hairs 4-10 mm, mostly silky, plicate;

lemmas 4.2-6.4 mm, lanceolate, 5-7 veined, distinctly keeled, glabrous, or the keels and marginal veins, sometimes also the lateral veins, densely long-villous, margins glabrous, apices acute;

palea keels scabrous, glabrous or sometimes softly puberulent to long-villous at midlength.

calluses glabrous or sparsely dorsally webbed, hairs plicate, rarely with additional webs under the marginal veins;

lemmas 3.5-5 mm, lanceolate, distinctly keeled, keels and marginal veins sparsely short- to long-villous, margins glabrous, apices acute;

palea keels scabrous, glabrous or softly puberulent to long-villous at midlength;

anthers vestigial (0.1-0.2 mm) or 1.6-2.7 mm.

= 42, ca. 54, 56, ca. 63, 84.

= unknown.