Flora of North America species comparison

1-12 cm, slender.

35-80 cm, erect or the bases decumbent, terete or weakly compressed;

nodes terete, 1-2 exserted.

closed for 1/6 – 1/4 their length, terete;

ligules 1-3 mm, milky white to hyaline, smooth;

blades 0.5-2 mm wide, flat or folded, or slightly inrolled, thin, without papillae (at 100x), apices narrowly prow-shaped.

closed for 1/3-1/4 their length, terete to slightly compressed, at least some proximal sheaths densely retrorsely scabrous, hispidulous, or softly puberulent for the upper 1/4 of their length, bases of basal sheaths glabrous, distal sheath lengths (1.4)1.7-4.6(6.2) times blade lengths;

collars of proximal leaves glabrous or with hairs the same length as those of their sheaths;

ligules 0.5-2 mm, smooth or scabrous, sometimes puberulent, truncate, those of the lower culm and innovation leaves 0.5-1.5 mm, abaxial surfaces scabrous to softly puberulent, truncate;

innovation blades folded or involute, infrequently flat, moderately thick, soft, adaxial surfaces usually densely scabrous to hispidulous;

cauline blades 2-3.5 mm wide, flat or folded, smooth or sparsely scabrous, glabrous or hispidulous, apices narrowly to broadly prow-shaped, blades gradually reduced distally or the middle blades longest, flag leaf blades 1-10 cm long.

all or mainly intra-vaginal.

mainly extra-vaginal.

1-3 cm, erect, contracted, usually exserted from the sheaths;

branches to 1.5 cm, erect to steeply ascending, slender, sulcate or angled, smooth or the angles sparsely scabrous;

pedicels shorter than the spikelets.

5-12(18) cm, erect or nodding, ovoid to pyramidal, loosely contracted to open, with 20-70 spikelets, proximal internodes usually shorter than 3.5 cm;

nodes with 2-5 branches;

branches (1)1.7-6.5 cm, ascending to spreading or reflexed, lax, terete or weakly angled, sparsely to moderately scabrous, with 2-8(12) spikelets.

3-4 mm, laterally compressed, green or anthocyanic;

florets 2-3;

rachilla internodes shorter than 1 mm, smooth.

5.5-10 mm, lengths to 3.5 times widths, laterally compressed, not sexually dimorphic;

florets 2-7;

rachilla internodes smooth or scabrous, glabrous or sparsely to densely hispidulous.

usually equaling or exceeding the lowest lemmas, sometimes also equaling or exceeding the upper florets, lanceolate to broadly lanceolate, distinctly keeled, keels smooth;

lower glumes 3-veined;

calluses glabrous;

lemmas 2.5-3 mm, lanceolate, distinctly keeled, thin, usually glabrous, keels and marginal veins rarely sparsely puberulent proximally, apices acute;

palea keels scabrous;

anthers 0.2-0.8 mm.

1/4 - 2/3(3/4) as long as the adjacent lemmas, lanceolate, distinctly keeled;

lower glumes 1-3-veined, 1/4-1/2 as long as the adjacent lemmas;

calluses glabrous;

lemmas 3-6 mm, lanceolate, distinctly keeled, keels and marginal veins glabrous or softly puberulent to short-villous, intercostal regions glabrous or hispidulous, infrequently puberulent, smooth or finely scabrous, lateral veins obscure to moderately prominent, margins glabrous, apices acute;

palea keels scabrous, intercostal regions glabrous;

anthers usually vestigial (0.1-0.2 mm) or aborted late in development and up to 2 mm, rarely normal.

= 14.

= 56, 61, 62, 63, 64, 66, 61, 70, ca. 74, 75, 79, 80, 81, 87, 89, 90, 91.