Flora of North America species comparison

20-60(100) cm, bases decumbent or sometimes erect, terete, with 1-2 exserted nodes.

20-65 cm, erect or the bases decumbent, terete or weakly compressed;

nodes terete, 1-2 exserted.

closed for 1/10 – 1/5(1/4) their length, terete, bases of basal sheaths glabrous;

ligules 2-5 mm, milky white, smooth or sparsely scabrous, acute to acuminate;

innovation blades similar in texture and shape to the cauline blades;

cauline blades not greatly reduced upwards, 1.5-4(5) mm wide, flat or folded, thin, lax, smooth or sparsely scabrous, apices narrowly prow-shaped.

closed for 2/3 – 9/10 their length, terete to slightly compressed, smooth or sparsely scabrous, sometimes hairy, hairs about 0.15 mm, bases of basal sheaths glabrous, distal sheath lengths (0.7)1-2.2(2.8) times blade lengths;

collars of proximal leaves usually hairy on and near the margins, marginal hairs longer than those of the sheaths;

ligules 0.5-1.5 mm, smooth or scabrous, hairy, hairs about 0.15 mm, truncate to obtuse, those of the lower culm and innovation leaves 0.5-1 mm, scabrous or softly puberulent, truncate;

innovation blades similar to or longer than the cauline blades;

cauline blades 2-4.5 mm wide, usually flat, lax, adaxial surfaces smooth or sparsely scabrous, particularly over the veins, apices broadly prow-shaped, blades gradually reduced in length distally or the middle blades longest, flag leaf blades 3-8 cm long.

mostly extravaginal, some intravaginal.

mainly extravaginal.

5-18(25) cm, lax, loosely contracted to open, sparse, with 20-65 spikelets and usually 2(7) branches per node;

branches 3-15 cm, ascending to spreading, angled, angles finely to coarsely, sparsely to fairly densely scabrous, infrequently smooth, with 3-10(15) spikelets in the distal 1/2.

8-15 cm, erect or lax, ovoid to pyramidal, open or loosely contracted, sparse, with 25-80 spikelets, proximal internodes 1.8-3.5 cm;

nodes with 3-5 branches;

branches 2.5-8 cm, ascending to spreading, lax, terete to weakly angled, moderately scabrous, with 2-8 spikelets.

6-10 mm, lengths 3-3.6 times widths, lanceolate to narrowly ovate, laterally compressed, sometimes bulbiferous, drab, often slightly glaucous;

florets 3-4(7), normal or bulb-forming;

rachilla internodes 1.2-2 mm, slightly dorsally compressed, smooth or sparsely muriculate.

4-7 mm, lengths to 3.5 times widths, laterally compressed, not sexually dimorphic;

florets 3-8;

rachilla internodes smooth or scabrous, glabrous or sparsely hispidulous.

subequal, lanceolate to broadly lanceolate, dull, frequently glaucous, obtuse to acute;

lower glumes 3-veined;

upper glumes (3.7)4.1-6.5 mm;

calluses usually crowned with 0.2-2 mm hairs, sometimes glabrous;

lemmas 4-6 mm, lanceolate, distinctly compressed, distinctly keeled, keels, marginal veins, and sometimes the lateral veins short- to long-villous, hairs extending for 3/4 of the keel, intercostal regions glabrous, sparsely puberulent or hispidulous proximally, usually sparsely to moderately densely scabrous distally, hairs distinctly shorter than those of the keel and veins, margins weakly inrolled, broadly scarious, glabrous, apices acute;

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

anthers 1.2-2 mm, sometimes aborted late in development or undeveloped.

2/3 – 4/5 as long as the adjacent lemmas, lanceolate, distinctly keeled;

lower glumes 1-3(5)-veined;

calluses usually glabrous, rarely minutely webbed;

lemmas 3-4.5 mm, lanceolate, distinctly keeled, keels and marginal veins usually glabrous, infrequently sparsely softly puberulent to short-villous, intercostal regions glabrous or hispidulous, smooth or finely scabrous, margins glabrous, apices acute;

paleas scabrous over the keels, intercostal regions glabrous;

anthers usually 2.5-4 mm, sometimes vestigial (0.1-0.2 mm).

= 42, [81, 84, 86?].

= 28, 28+1.