Flora of North America species comparison

5-40(80) cm, erect to spreading, straight, wiry, bases straight or slightly decumbent;

nodes terete or slightly compressed, usually 0-1 exserted, top node at 1/10-1/3 the culm length.

7-30 (35) cm tall, 0.4-0.9 mm thick, slender, erect or the bases decumbent, terete or weakly compressed;

nodes terete, 0-1 exserted.

closed for 1/10 – 1/5 their length, terete, bases of basal sheaths glabrous or sparsely minutely hairy, hairs 0.1-0.2 mm, distal sheath lengths 1.1-4 times blade lengths;

ligules 1-4(5) mm, sparsely to densely scabrous, apices obtuse to acute, minutely ciliolate;

blades 0.8-2.5 mm wide, flat or folded, thin, soft, appressed or abruptly ascending to spreading, straight, apices narrowly prow-shaped.

closed for 1/3-2/3 their length, terete, smooth, glabrous, bases of basal sheaths glabrous, distal sheath lengths (1)1.4-4.5 times blade lengths;

collars smooth, glabrous;

ligules 0.5-1.5(2.2) mm, scabrous, truncate to acute;

innovation blades adaxially moderately to densely scabrous or hispidulous on and between the veins;

cauline blades slightly reduced in length distally, 0.5-1(1.5) mm wide, involute, thin to moderately thick, usually filiform, soft, abaxial surfaces smooth, adaxial surfaces sparsely scabrous on and between the veins, apices narrowly prow-shaped, flag leaf blades (0.5)1-5 cm.

all or mostly extravaginal.

mainly intravaginal, some extravaginal.

1-10(20) cm, lengths 3-5 times widths at maturity, rarely racemelike with branches of irregular length, erect, narrowly lanceoloid to ovoid, contracted to somewhat open, sparse, proximal internodes shorter than 1.5(4) cm;

nodes with 2-3(5) branches;

branches erect, ascending or weakly spreading, fairly straight, short, stout, angled, angles moderately to densely scabrous, rarely only scabrous distally, glaucous;

pedicels usually shorter than the spikelets.

1-5(7) cm, erect, ovoid, fairly tightly to loosely contracted, congested or moderately congested, with fewer than 50 spikelets;

nodes with 1-2 branches;

branches 0.5-3 cm, erect to ascending, slightly lax, terete or angled, angles sparsely to densely scabrous, with 2-12 spikelets.

3-7(9) mm, lengths 2-3 times widths, laterally compressed, rarely bulbiferous, usually glaucous;

florets 2-5, rarely bulb-forming;

rachilla internodes to 1.2 mm, smooth, muriculate, or scabrous, glabrous or sparsely to densely hispidulous or puberulent.

3-6(8) mm, lengths to 3 times widths, laterally compressed, compact, not sexually dimorphic;

florets 2-5;

rachilla internodes 0.8-1.1 mm, usually not readily visible from the sides, glabrous or sparsely puberulent.

subequal, narrowly to broadly lanceolate, distinctly keeled, keels smooth or sparsely scabrous, apices acute;

lower glumes 3-veined;

upper glumes 2-3.8(5.2) mm, lengths usually more than 4.1 times widths, distinctly shorter to subequal to the lowest lemmas;

calluses glabrous or webbed, webs from minute to more than 1/2 the lemma length;

lemmas 2.5-4 mm, lanceolate to broadly lanceolate, distinctly keeled, keels and marginal veins short-villous, lateral veins obscure, usually sparsely softly puberulent to short-villous, intercostal regions smooth, sometimes weakly muriculate, glabrous or puberulent, margins glabrous, apices usually partially bronze-colored, obtuse or acute;

palea keels scabrous, glabrous or softly puberulent at midlength, intercostal regions glabrous or softly puberulent;

anthers (1)1.2-2.5 mm, mature sacs 0.2 mm wide, rarely aborted late in development.

slightly unequal, distinctly keeled, keels smooth or scabrous;

lower glumes 2-4 mm, 1-3-veined, about 2/3 the length of the adjacent lemmas;

upper glumes 2.9-5 mm;

calluses usually diffusely webbed, hairs 1-2 mm, infrequently glabrous;

lemmas 2.5-4(4.5) mm, lanceolate, distinctly keeled, moderately to densely finely scabrous, glabrous throughout or the keels and sometimes the marginal veins sparsely puberulent proximally, margins narrowly scarious, glabrous, apices acute;

paleas subequal to the lemmas, keels scabrous, intercostal regions glabrous;

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

= 34, 42, 44, 47, 48, 49, 50, 56, 56, 57, 58, 60, 63, 64, 65, 70, 75, 78, ca. 100.

= 42.