Flora of North America species comparison

30-350(400) cm, usually erect, much branched above the bases.

not aromatic;

ligules membranous, not ciliate;

blades usually flat or folded.

false panicles with numerous inflorescence units;

peduncles with 2 rames in digitate clusters;

rames with naked, often deflexed bases, axes without a translucent median groove;

disarticulation in the rames, beneath the bisexual spikelets.

in sessile-pedicellate pairs, basal 1-2 pairs on each rame homogamous, morphologically similar to the heterogamous pairs, staminate or sterile, unawned, not forming an involucre, tardily deciduous, remaining pairs heterogamous.

oblong, subterete.

slender, not adnate to the rame axes.

spikelet units: sessile spikelets dorsally compressed or subterete;

calluses blunt to sharp, strigose;

glumes equal, pubescent;

lower glumes coriaceous, rounded, without keels, truncate to slightly bilobed;

upper glumes narrower, shallowly keeled;

lower florets sterile, reduced;

upper florets bisexual, awned from between the teeth of the bifid lemma;

awns usually present, to 3.5(19) cm, pubescent on the lower portion.

spikelets usually slightly longer than the sessile spikelets, staminate or sterile, usually unawned, lower glumes sometimes aristulate.

= 10, 15.