Flora of North America species comparison

annual, not woody, not branching above the base;

internodes hollow.

(4)9-250 cm, sometimes forming a basal corm;

nodes and internodes usually glabrous.

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;

auricles sometimes present;

ligules thinly membranous, erose to lacerate, usually glabrous, those of the lower leaves shorter than those of the upper leaves;

blades flat or folded, glabrous or hairy, particularly on the adaxial surfaces, sometimes scabrous.

terminal panicles or racemes;

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

terminal panicles;

primary branches often appressed;

secondary branches appressed or divergent;

pedicels either more or less straight or sharply bent below the spikelets, scabrous to strigose distally;

disarticulation below the glumes in species with sharply bent pedicels, above the glumes in other species.

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.

with 1-7 bisexual florets, terminating in a sterile structure, the rudiment, composed of 1-4 sterile florets;

rudiments sometimes morphologically distinct from the bisexual florets, sometimes similar but smaller.

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.

membranous or chartaceous, distal margins wide, translucent;

lower glumes 1-9-veined;

upper glumes 1-11-veined;

calluses glabrous;

lemmas membranous basally, sometimes becoming coriaceous at maturity, glabrous or with hairs, (4)5-15-veined, usually unawned, sometimes awned, awns to 12 mm, straight;

paleas from 1/2 as long as to almost equaling the lemmas, keels usually ciliate;

lodicules fused into a single, collarlike structure extending 1/2 - 2/3 around the base of the ovaries;

anthers (2)3.

ovoid to ellipsoid, longitudinally grooved or not;

hila usually linear;

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

usually 2-3 mm, smooth, glabrous, longitudinally furrowed, falling from the floret when mature, x = 9.

= (8)9, 10.