Flora of North America species comparison

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

nodes terete, 0-1 exserted.

(15)20-40 cm, erect or decumbent, with 1-2 exserted nodes.

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 1/5-1/3 their length, terete, smooth, bases of basal sheaths glabrous, distal sheath lengths 4-33 times blade lengths, smooth, glabrous;

ligules (1.5)2-5 mm, smooth or sparsely scabrous, margins distinctly decurrent, apices obtuse to acute, ligules of innovations prominent, milky white;

innovation blades similar to the cauline blades;

cauline blades gradually reduced in length upwards, (1)1.5-3 mm wide, flat, thick, fairly firm, smooth or sparsely scabrous, margins white, apices broadly prow-shaped, flag leaf blades 0.2-1.8 cm, infrequently absent.

intra- and extravaginal.

mainly intravaginal.

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.

4-8 cm, erect, linear to narrowly lanceoloid, contracted, moderately congested, with 9-35 spikelets;

nodes with 1-2 branches;

branches 1-2.5 cm, erect to steeply ascending, straight, sulcate or angled, angles sparsely to moderately scabrous, with 1-4 spikelets in the distal 1/2.

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.

7-9 mm, lengths 3.5-4 times widths, lanceolate, fairly compressed, pale, slightly lustrous;

florets (2)3-4;

rachilla internodes 1-2 mm.

unequal, distinctly keeled, keels and lateral veins scabrous;

lower glumes 1-3-veined.

lanceolate to broadly lanceolate, margins broadly scarious, keels indistinct, smooth or sparsely scabrous;

lower glumes 3-veined, slightly to distinctly shorter than the lowest lemma;

calluses glabrous;

lemmas 4.5-6 mm, lanceolate, somewhat weakly keeled, glabrous or the keels, marginal veins, and intercostal regions very sparsely puberulent over the proximal 1/3, lateral veins obscure, margins strongly inrolled proximally, broadly scarious distally, glabrous, apices acute;

palea keels scabrous, glabrous or puberulent at midlength;

anthers 2.2-3.5 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.

= 42.