Flora of North America species comparison

29-100 cm, forming corms, corms almost sessile on the connecting rhizomes;

internodes scabridulous above the nodes.

annual, not woody, not branching above the base;

internodes hollow.

usually scabridulous, sometimes sparsely pilose;

ligules 2-6 mm;

blades 1.5-5 mm wide, abaxial surfaces scabridulous, adaxial surfaces with hairs.

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.

7-30 cm;

branches 2-6.5 cm, appressed, usually straight, with 1-5 spikelets;

pedicels straight;

disarticulation above the glumes.

terminal panicles or racemes;

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

6-24 mm, with 4-7 bisexual florets, base of the distal florets concealed at anthesis;

rachilla internodes 1-2 mm, not swollen when fresh, not wrinkled when dry.

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.

from (1/2)2/3 as long as to equaling the spikelets;

lower glumes 5.5-10.5 mm long, 2-3 mm wide, 3-5-veined;

upper glumes 6-14 mm long, 2.3-3.5 mm wide, 5-7-veined;

lemmas 6-12 mm, glabrous, smooth or scabrous, 7-11-veined, veins prominent, apices emarginate to acute, unawned;

paleas about 3/4 the length of the lemmas;

anthers 3, 1.5-4 mm;

rudiments 1.5-5 mm, truncate to tapering, sometimes resembling the bisexual florets in shape.

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.

ovoid to ellipsoid, longitudinally grooved or not;

hila usually linear;

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

= (8)9, 10.

=18.