Flora of North America species comparison

annual, not woody, not branching above the base;

internodes hollow.

30-110 cm, glabrous, often decumbent at the base;

nodes glabrous, becoming dark.

closed for their whole length or almost so;

collars without tufts of hair on the sides;

auricles sometimes present;

ligules hyaline, glabrous, often lacerate, occasionally ciliate, those of the lower and upper cauline leaves usually similar;

pseudopetioles absent;

blades linear to narrowly lanceolate, venation parallel, cross venation sometimes evident;

cross sections non-Kranz, without arm or fusoid cells;

epidermes without microhairs, sometimes papillate.

closed almost to the top;

ligules membranous, margins often united in front;

blades folded or loosely involute, glabrous or pilose.

terminal panicles or racemes;

disarticulation above the glumes and beneath the florets or below the glumes.

panicles or racemes, with 4-20 spikelets;

branches straight and appressed to lax and drooping.

2.5-60 mm, not viviparous, slightly to strongly laterally compressed, with 1-30 florets, proximal florets bisexual, distal 1-3 florets usually sterile, sometimes pistillate, sometimes reduced and amalgamated into a knob- or club-shaped rudiment;

rachillas prolonged beyond the base of the distal floret.

slightly laterally compressed, with 3-6 florets;

disarticulation above the glumes and beneath the florets.

exceeded by the distal florets, shorter than to longer than the adjacent lemmas, mostly membranous, scarious distally, 1-11-veined, apices usually rounded to acute;

florets laterally or dorsally compressed;

calluses blunt, glabrous or with hairs;

lemmas of sexual florets rectangular or ovate, mostly membranous, scarious distally, often with a purplish band adjacent to the scarious apices, (4)5-15-veined, veins not converging distally, often prominent, unawned or awned, awns not branched, apices entire to bilobed or bifid, awns straight, subterminal or from the sinuses;

paleas from shorter than to longer than the lemmas, similar in texture, 2-veined, veins keeled, sometimes winged;

lodicules 2, fleshy, usually connate into a single structure, without a membranous wing, truncate, not ciliate, not or scarcely veined;

anthers 1, 2, or 3;

ovaries glabrous;

styles 2-branched, bases persistent, branches plumose distally.

exceeded by the lowest lemma in each spikelet, chartaceous, often anthocyanic below, the upper 1/3 hyaline;

calluses rounded, with hairs;

lemmas chartaceous, slightly scabrous, 7-9-veined, veins parallel, conspicuous, apices scarious, bifid, awned from below the teeth, awns 8-15 mm, divergent or slightly geniculate;

paleas shorter than the lemmas, 2-veined, veins ciliate, keeled;

lodicules truncate;

anthers 3;

ovaries glabrous.

ovoid to ellipsoid, longitudinally grooved or not;

hila usually linear;

embryos less than 1/3 as long as the caryopses.

3.2-3.8 mm, smooth, shiny, falling free of the lemma and palea.

= (8)9, 10.

= 10.