Flora of North America species comparison

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

nodes terete, usually 1 exserted.

20-65 cm, erect or the bases decumbent, not branching above the base, terete or weakly compressed;

nodes terete, 1-2 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 1/2-1/3 their length, slightly compressed, keels moderately distinct, smooth or sparsely to moderately scabrous, glabrous, bases of basal sheaths glabrous, distal sheath lengths 1.5-4.4(5.7) times blade lengths;

collars smooth, glabrous;

ligules of cauline leaves 2-8 mm, smooth or scabrous, acute to acuminate, innovation ligules 2-5 mm;

innovation blades to 20 cm, otherwise similar to the cauline blades;

cauline blades gradually reduced in length distally, 1-3.5 mm wide, usually flat or folded, soft, thin, somewhat lax, smooth or sparsely scabrous, primarily over the veins and margins, distinctly keeled, apices narrowly to broadly prow-shaped, flag leaf blades (1.4)3-6(8) cm.

intravaginal, innovations common, similar to the culms.

all or mainly extra vaginal.

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)4-10 cm, nodding, ovoid, sparse, with 20-50 spikelets, proximal internodes usually 1.8-3 cm;

nodes with 1-2(4) branches;

branches 1.5-4.5 cm, ascending to spreading, lax, terete to weakly angled, angles sparsely to moderately scabrous, with 2-7 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.

(4)6-9(12) mm, lengths to 3.5 times widths, laterally compressed, not sexually dimorphic;

florets 3-8, usually unisexual;

rachilla internodes smooth or sparsely scabrous, usually glabrous, infrequently sparsely puberulent.

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, narrowly lanceolate to lanceolate, distinctly keeled, keels scabrous;

lower glumes 1-3(5)-veined;

calluses webbed, hairs over 1/2 the lemma length;

lemmas 4-6.5 mm, lanceolate, 5-7-veined, distinctly keeled, keels and marginal veins sparsely short- to long-villous, lateral veins moderately prominent, intercostal regions sparsely scabrous, glabrous, margins glabrous, apices acute;

palea keels scabrous;

anthers vestigial (0.1-0.2 mm) or 2.5-4 mm.

= 28.

=28.