Flora of North America species comparison

30-140 cm tall, 1-1.8 mm thick, erect or geniculate, internodes glabrous;

nodes usually 2-4, exposed, sericeous, hairs to 1.2 mm.

10-175(210) cm, sometimes branched at the upper nodes, branches flexible;

prophylls not evident, shorter than the sheaths.

glabrous or slightly hispid, basal leaf sheaths often with cleistogenes;

collars glabrous, often brown or purple-tinged, with tufts of hair at the sides, hairs 0.5-1.2 mm;

Iigules 1-4 mm, glabrous or pubescent, truncate;

blades to 30 cm long, 2-8 mm wide, flat to convolute, sometimes scabrous, sometimes with hairs.

mostly basal, not overwintering;

sheaths open;

cleistogenes sometimes present;

auricles absent;

ligules membranous, sometimes pubescent or ciliate;

blades of basal leaves 3-60 cm long, 0.2-8 mm wide, apices narrowly acute to acute, not sharp, flag leaf blades 1-80 mm, bases about as wide as the top of the sheaths.

terminal panicles, sometimes partially included at maturity.

3-22 mm, with 1 floret;

rachillas not prolonged beyond the base of the floret;

disarticulation above the glumes, beneath the floret.

subequal, 10-22 mm long, 1.8-2.3 mm wide, narrowly lanceolate, glabrous, 3-5-veined;

florets 6-13 mm long, 1-1.5 mm wide, terete, widest just below the crown;

calluses 2-4.5 mm, sharp, strigose;

lemmas often purple, finely rugose-papillose, particularly near the crown, constricted below the crown, midveins pilose proximally, glabrous between the veins at maturity;

crowns 0.4-1.6 mm, usually wider than long, sides usually flaring somewhat distally, rims with hairs to 0.5 mm;

awns 50-120 mm, clearly twice-geniculate, terminal segment straight;

anthers 3-3.5 mm, penicillate.

longer than the floret, narrowly lanceolate or ovate, basal portion usually purplish at anthesis, color fading with age, (1)3-5-veined, sometimes awned;

florets usually terete, sometimes slightly laterally compressed;

calluses blunt or sharp, glabrous or antrorsely strigose;

lemmas usually papillose or tuberculate, at least distally, sometimes smooth throughout, glabrous or variously hairy, strongly convolute, wrapping 1.2-1.5 times around the caryopses, apices not lobed, fused distally into crowns, these often evident by their pale color and constricted bases;

crowns mostly glabrous, rims often bearing hairs with bulbous bases;

awns terminal, centric or eccentric, deciduous or persistent, usually twice-geniculate, second geniculation often obscure;

paleas up to 1/2 as long as the lemmas, glabrous, without veins, flat;

lodicules 2 or 3, if 3, the third somewhat shorter than the other 2;

anthers 1 or 3, if 3, often of 2 lengths, penicillate;

ovaries glabrous;

styles 2, bases free.

3-5 mm.

glabrous, not ribbed;

hila elongate;

embryos to 2/5 as long as the caryopses.

panicles 5-40 cm, exserted, erect to nodding;

branches 2.5-8.5 cm, with 2-5 spikelets;

pedicels 1-8 mm, angled, scabrous, pubescent.

= 7, 8.

= 28.