Flora of North America species comparison

15-60 cm, erect.

30-75 cm, erect.

glabrous;

ligules 0.7-1 mm;

blades to 20 cm long, 2-4 mm wide, without basal hairs, glabrous or scabrous, upper cauline leaves often greatly reduced.

glabrous;

ligules about 0.5 mm, shortly ciliate;

blades to 20 cm long, to 5 mm wide, sometimes with long basal hairs, otherwise scabrous.

with 10-20 branches in several closely-spaced whorls;

branches 2-5 cm, spreading, with 14-18 spikelets per cm;

disarticulation beneath the glumes.

with 5-17, evidently distinct branches in 1-3 closely-spaced whorls;

branches to 7 cm, usually erect when young, spreading to reflexed at maturity, averaging 12 spikelets per cm.

with 1 bisexual and 1 sterile floret.

with 1 bisexual and 1 staminate floret.

0.5-0.7 mm;

upper glumes 1-1.5 mm;

lowest lemmas 1.5-2 mm long, 0.7-1 mm wide, broadly elliptic, mostly glabrous but the keels and marginal veins appressed-pilose, obtuse, awned, awns 0.3-1.5 mm;

second florets 1-1.5 mm long and about equally wide, conspicuously inflated, spherical, with the distal portion of the margins inrolled, not or inconspicuously bilobed, lobes less than 1/5 as long as the lemmas, midveins sometimes excurrent to 1.5 mm.

1.5-3.2 mm;

upper glumes 2.5-3.4 mm;

lowest lemmas 2.8-3.7 mm long, 0.6-1.1 mm wide, broadly linear to elliptic, mostly glabrous but the margins appressed pubescent, apices obtuse, not conspicuously bilobed, sometimes shortly mucronate;

second florets 1.4-2.2 mm long, 0.3-0.9 mm wide, usually at least twice as long as wide, not lobed, unawned, occasionally mucronate.

0.9-1.2 mm long, about 0.5 mm wide, obovoid.

1.7-2.3 mm long, 0.5-0.6 mm wide, ellipsoid.

= 40.

= ca. 65, 80.