Flora of North America species comparison

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

nodes terete, usually 1 exserted.

20-40(75) cm, erect or the bases decumbent, not branching above the base, terete or weakly compressed;

nodes terete, proximal nodes usually 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 2/5 – 1/2 their length, terete, glabrous, smooth or slightly scabrous, bases of basal sheaths glabrous, distal sheath lengths (1)1.2-3.5 times blade lengths;

collars smooth, glabrous;

ligules 1.5-4(6) mm, smooth, apices obtuse to acute, not ciliate;

blades 1-3.5(5) mm wide, folded or flat, innovation shoot blades involute, soft, abaxial surfaces glabrous, adaxial surfaces smooth or sparsely scabrous, frequently sparsely hairy with 0.2-0.8 mm hairs, slender, erect to appressed, curving, sinuous or straight, apices narrowly prow-shaped, cauline blades subequal, flag leaf blades 1.5-8 cm.

intravaginal, innovations common, similar to the culms.

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.

5-9(17) cm, narrowly lanceoloid to narrowly pyramidal, loosely contacted to open, sparse, with 25-60 spikelets and 2-5 branches per node;

branches 1-3 cm, ascending to spreading, slightly flexuous to fairly straight, terete, smooth or sparsely scabrous, usually with 1-5 spikelets per branch, the spikelets moderately crowded in the distal 1/2.

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.

4-6.5(8) mm, lengths to 3 times widths, laterally compressed;

florets 2-4(6);

rachilla internodes shorter than 1 mm, smooth, usually glabrous, rarely with a few hairs.

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.

unequal to subequal, usually distinctly shorter than the adjacent lemmas, lanceolate, distinctly keeled, keels smooth to sparsely scabrous;

lower glumes 2.8-3.5 mm, narrowly lanceolate, (1)3-veined;

upper glumes 4-4.5(5) mm, distinctly shorter than to nearly equaling the lowest lemmas;

calluses dorsally webbed, webs copious, hairs at least 1/2 times the lemma length, sometimes secondary webs present under the marginal veins;

lemmas 3.7-4.5(5) mm, lanceolate, usually strongly purple, distinctly keeled, keels, lateral veins, and marginal veins copiously hairy, hairs cottony, lateral veins prominent, less hairy, intercostal regions glabrous, usually smooth or finely muriculate, sometimes sparsely scabrous distally, margins narrowly hyaline, glabrous, apices acute;

palea keels sparsely scabrous, long-villous at midlength, intercostal regions narrow, glabrous;

anthers 1.8-2.5 mm.

= 28.

= 56, ca. 70.