Flora of North America species comparison

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

25-65 cm, erect or spreading, basal branching extravaginal;

prophylls not visible;

nodes glabrous.

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;

cleistogenes not developed;

sheaths open, glabrous;

auricles absent;

ligules membranous, longest at the sides or rounded, ciliate;

blades of basal leaves 30-90 cm, remaining green over winter, erect when young, recumbent in the fall, bases twisted, placing the abaxial surfaces uppermost, cauline leaf blades reduced, flag leaf blades 2-12 mm, conspicuously narrower than the top of the sheath.

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

panicles, contracted.

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.

5-7.5 mm, with 1 floret;

rachillas not prolonged beyond the base of the floret;

disarticulation above the glumes, beneath 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, 6-10-veined, apices mucronate;

florets terete to laterally compressed;

calluses usually less than 1/5 the length of the florets, blunt, distal portions pilose;

lemmas coriaceous, pubescent at least basally, 3-5(9)-veined, margins strongly overlapping at maturity, awned, lemma-awn junction conspicuous, lobed, lobes 0.1-0.2 mm;

awns more or less straight, deciduous;

paleas similar to the lemmas in length, texture, and pubescence, concealed by the lemmas, 2-veined, flat between the veins;

lodicules 2, free, membranous, 2-veined;

anthers 3;

styles 1, with 2 branches;

ovaries glabrous.

ovoid to fusiform, not beaked, pericarp thin;

hila linear;

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

falling with the lemma and palea.

= 7, 8, 10, 11, 12.

= 11, 12.