Flora of North America species comparison

annual or perennial, not woody, branches 1 to many at the upper nodes.

10-60 cm tall, 0.4-1.2 mm thick, erect, glabrous, not branching at the upper nodes;

nodes 1, exposed;

basal branching intravaginal;

prophylls shorter than the sheaths.

basally concentrated to evenly distributed;

sheaths open, margins not fused, sometimes ciliate distally, basal sheaths sometimes concealing axillary panicles (cleistogenes), sometimes wider than the blade;

collars sometimes with tufts of hair at the sides extending to the top of the sheaths;

auricles absent;

ligules scarious, often ciliate, cilia usually shorter than the base, ligules of the lower and upper cauline leaves sometimes differing in size and vestiture;

pseudopetioles absent;

blades linear to narrowly lanceolate, venation parallel, cross venation not evident, cross sections non-Kranz, without arm or fusoid cells;

epidermes of adaxial surfaces sometimes with unicellular microhairs, cells not papillate.

mostly basal, not overwintering;

cleistogenes not developed;

sheaths open for most of their length, glabrous, smooth to somewhat scabrous;

auricles absent;

ligules 0.2-3 mm, membranous, rounded to acute, glabrous, not ciliate;

blades convolute, 0.2-0.6 mm in diameter, apices stiff, flag leaf blades longer than 1 cm.

usually terminal panicles, occasionally reduced to racemes in depauperate plants, sometimes 2-3 panicles developing from the highest cauline node.

terminal panicles;

branches capillary, often flexuous, sometimes straight, glabrous or sparsely hirtellous;

disarticulation above the glumes, beneath the floret.

usually with 1 floret, sometimes with 2-6 florets, laterally compressed to terete;

rachillas not prolonged beyond the base of the floret in spikelets with 1 floret, prolonged beyond the base of the distal floret in spikelets with 2-6 florets, prolongation hairy, hairs 2-3 mm;

disarticulation above the glumes and beneath the florets.

3.4-7 mm, with 1 floret;

rachillas not prolonged beyond the floret.

usually exceeding the floret(s), always longer than 1/4 the length of the adjacent floret, 1-10-veined, narrowly lanceolate to ovate, hyaline or membranous, flexible;

florets usually terete, sometimes laterally or dorsally compressed;

calluses usually well-developed, rounded or blunt to sharply pointed, often antrorsely strigose;

lemmas lanceolate, rectangular, or ovate, membranous to coriaceous or indurate, 3-5-veined, veins inconspicuous, apices entire, bilobed, or bifid, awned, lemma-awn junction usually conspicuous, awns 0.3-30 cm, not branched, usually terminal and centric or eccentric, sometimes subterminal, caducous to persistent, not or once- to twice-geniculate, if geniculate, proximal segment(s) twisted, distal segment straight, flexuous, or curled, not or scarcely twisted;

lodicules 2 or 3;

anthers 1 or 3, sometimes differing in length within a floret;

ovaries glabrous throughout or pubescent distally;

styles 2(3-4)-branched.

subequal, hyaline, mostly purplish, venation not evident, apices rounded to acute;

florets slightly shorter than the glumes, terete;

calluses 0.1-0.8 mm, blunt, hairy;

lemmas thickly membranous, smooth, hairy over the basal portion or throughout, hairs 0.2-0.4 mm, margins flat, not overlapping at maturity, apices lobed, lobes 0.1-1 mm, membranous, apices with a single terminal awn, lemma-awn junction evident;

awns 5-30 mm, centric, persistent, once- or twice-geniculate, sometimes weakly so, scabrous or hairy, hairs to 2 mm;

paleas slightly shorter to slightly longer than the lemmas, hairy, hairs to 0.5 mm, 2-veined, not keeled over the veins, flat between the veins, veins ending before the apices, apices rounded;

lodicules 3, free, membranous;

anthers 3, 0.4-3.3 mm, sometimes penicillate;

ovaries glabrous;

styles 2, white, free to the base.

ovoid to fusiform, not beaked, pericarp thin;

hila linear;

embryos less than 1/3 the length of the caryopses.

2-5 mm, fusiform, not ribbed, x = unknown.

= 7, 8, 10, 11, 12.