Flora of North America species comparison

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

nodes terete, usually 1 exserted.

10-50 cm, erect or the bases decumbent, terete or weakly compressed;

nodes terete, 0-1 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 1/3 – 7/8 their length, terete to slightly compressed, smooth, glabrous, bases of basal sheaths glabrous, distal sheath lengths (1.15)1.5-4.6(6.6) times blade lengths;

collars smooth, glabrous;

ligules 0.5-2(2.5) mm, smooth, truncate to obtuse;

innovation blades similar to the cauline blades;

cauline blades gradually reduced in length distally, 2-5 mm wide, flat or folded, smooth or the adaxial surfaces sparsely scabrous, primarily over the veins, apices broadly prow-shaped, flag leaf blades 0.7-6 cm.

intravaginal, innovations common, similar to the culms.

all or mainly 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.

2-9 cm, erect, lanceoloid to ovoid, tightly to loosely contracted, with 15-35 spikelets, proximal internodes shorter than 2 cm;

nodes with 1-2 branches;

branches 0.9-3.2 cm, erect to ascending or slightly spreading, terete, smooth or sparsely scabrous, with 1-4 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.

6-12 mm, lengths to 3 times widths, laterally compressed, not sexually dimorphic;

florets 2-7;

rachilla internodes 0.8-1.5 mm, smooth or sparsely scabrous, 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.

3/5- 4/5 as long as the adjacent lemmas, distinctly keeled;

lower glumes 3-veined;

calluses of at least some proximal florets sparsely webbed, with 1-2 mm hairs, others glabrous, rarely all glabrous;

lemmas 5-7 mm, lanceolate, 5-7-veined, distinctly keeled, smooth or sparsely finely scabrous, glabrous throughout or the keels and marginal veins sparsely softly puberulent over the proximal 1/4, lateral veins moderately prominent, intercostal regions glabrous, margins glabrous, apices acute;

palea keels sparsely scabrous, intercostal regions glabrous;

anthers vestigial (0.1-0.2 mm), aborted late in development, or 1.8-3.7 mm.

= 28.

= unknown.