Flora of North America species comparison

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

nodes terete, usually 1 exserted.

(15)30-80 cm, erect or the bases decumbent, terete or weakly compressed;

nodes terete, 1-3 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 1/2 - 9/10 their length, compressed, smooth, glabrous, bases of basal sheaths glabrous, distal sheath lengths 1-3 times blade lengths;

collars smooth, glabrous;

ligules 0.5-4 mm, smooth or sparsely scabrous, truncate to obtuse;

innovation blades similar to the cauline blades;

cauline blades 2-5 mm wide, flat, thin, smooth or sparsely scabrous mainly over the veins, apices broadly prow-shaped, middle and upper cauline blades subequal in length, flag leaf blades (2.5)4-7(11) cm long.

intravaginal, innovations common, similar to the culms.

all or mostly extravaginal.

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.

(5)12-22 cm, usually narrowly pyramidal, open, sparse, with 20-70 spikelets, proximal internodes usually (3.5)4+ cm, with 2-3(4) branches per node;

branches 3-8 cm, spreading to eventually reflexed, terete or weakly angled, sparsely to moderately scabrous, 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.

5-9 mm, lengths to 3.5 times widths, laterally compressed, not sexually dimorphic;

florets 2-6;

rachilla internodes smooth, glabrous, distal internodes 1+ mm.

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.

lanceolate, distinctly keeled;

lower glumes 1-3-veined;

calluses glabrous;

lemmas 3-6.5 mm, lanceolate, distinctly keeled, keels and marginal veins glabrous or short-villous to softly puberulent to 1/3 their length, lateral veins obscure, intercostal regions glabrous or sparsely hispidulous, rarely softly puberulent, smooth or sparsely finely scabrous, margins glabrous, apices acute;

palea keels scabrous, glabrous, intercostal regions glabrous;

anthers vestigial (0.1-0.2 mm) or (1.3)2-3.6 mm.

= 28.

= unknown.