Flora of North America species comparison

2-20(45) cm, prostrate to erect, slender;

nodes terete, usually 1 exserted.

10-55 cm, erect or the bases decumbent, terete or weakly compressed;

nodes terete, not exserted.

closed for about 1/3 their length, terete or weakly compressed, smooth;

ligules 0.5-3(5) mm, smooth, glabrous, decurrent, obtuse to truncate;

blades 1-10 cm long, 1-3(6) mm wide, flat or weakly folded, thin, soft, smooth, margins usually slightly scabrous, apices broadly prow-shaped.

closed for about 1/3 their length, terete, smooth, glabrous, bases of basal sheaths glabrous, distal sheath lengths 1.5-7.5 times blade lengths;

collars smooth, glabrous;

ligules 1-2 mm, smooth or sparsely scabrous, apices truncate to obtuse;

innovation blades similar to the cauline blades, adaxial surfaces nearly smooth, glabrous on and between the veins;

cauline blades fairly strongly reduced in length distally, 1-3 mm wide, folded to involute, moderately thick, moderately firm, abaxial surfaces smooth, apices narrowly prow-shaped, flag leaf blades 1-5.5 cm.

intravaginal, innovations common, similar to the culms.

extra- and intravaginal.

1-7(10) cm, lengths 1.2-1.6 times widths, erect;

nodes with 1-2(3) branches;

branches ascending to spreading or reflexed, straight, terete, smooth, with crowded or loosely arranged spikelets.

3-7 cm, erect, lanceoloid to ovoid, congested, with 20-70 spikelets;

nodes with 1-2 branches;

branches 0.5-3 cm, erect, terete, usually smooth, infrequently sparsely scabrous distally, with 3-12 spikelets.

3-5 mm, laterally compressed;

florets 2-6;

rachilla internodes smooth, glabrous, concealed or exposed, distal internodes less than 1/2(3/4) the length of the distal lemma.

3.5-5.5 mm, lengths to 3 times widths, laterally compressed, very compact, not sexually dimorphic;

florets 2-5;

rachilla internodes about 0.5 mm, smooth, glabrous.

smooth, distinctly keeled, keels smooth;

lower glumes 1-veined;

upper glumes shorter than or subequal to the lowest lemma;

calluses glabrous;

lemmas 2.5-4 mm, lanceolate, distinctly keeled, smooth throughout, the keels, marginal veins, and, usually, lateral veins crisply puberulent to long-villous, rarely glabrous throughout, lateral veins prominent, intercostal regions glabrous, margins smooth, glabrous, apices obtuse to acute;

palea keels smooth, usually short- to long-villous, rarely glabrous;

anthers 0.6-1.1 mm, oblong prior to dehiscence, those of the upper 1-2 florets usually vestigial.

broadly lanceolate, distinctly shorter than the adjacent lemmas, distinctly keeled, keels smooth or sparsely scabrous;

lower glumes 3-veined;

calluses glabrous;

lemmas 2.5-3.5 mm, lanceolate, usually purplish, distinctly keeled, glabrous, smooth, margins glabrous, apices acute;

palea keels scabrous, intercostal regions glabrous;

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

= 28.

= 28.