Flora of North America species comparison

60-120 cm, stiffly erect, unbranched.

annual, erect, solid or hollow, usually unbranched.

basal or nearly basal;

sheaths shorter than the internodes, smooth and mostly glabrous abaxially, sometimes with a line of widely spaced, 0.5-1 mm hairs over the midvein, not disintegrating into threadlike fibers at maturity;

collars glabrous, sometimes with a few conspicuous hairs at the sides;

ligules 0.1-0.3 mm;

blades 15-50 cm long, 0.3-1 mm wide, tightly involute, stiff, yellow-green, abaxial surfaces villous on both sides of the midvein, at least on the basal portion, hairs 0.6-1.5 mm, adaxial surfaces densely scabrous or densely short pubescent.

distichous;

sheaths usually open;

auricles absent;

abaxial ligules absent or of hairs;

adaxial ligules membranous and ciliate or of hairs;

blades without pseudopetioles;

mesophyll cells radiate or non-radiate;

adaxial palisade layer absent;

fusoid cells absent;

arm cells absent;

kranz anatomy absent or present, when present, with 1 or 2 parenchyma sheaths;

midribs simple;

adaxial bulliform cells present;

stomatal subsidiary cells dome-shaped or triangular;

bicellular microhairs present, with long, slender, thin-walled terminal cells.

paniculate, 20-35 cm, 5-8 mm wide;

nodes glabrous;

primary branches 2-5 cm, appressed, without axillary pulvini, with 4-12 spikelets, spikelet-bearing to the base.

terminal, not leafy, usually panicles, sometimes spikes or racemes;

disarticulation above the glumes.

appressed.

bisexual, with 1 floret;

rachilla extension absent.

subequal, glabrous, light brown or tan, usually 1(2)-veined, bifid and awned, awns 1.5-2.5 mm;

lower glumes 7-10 mm;

upper glumes 6-9 mm;

calluses 0.4-0.6 mm;

lemmas 6-9 mm, glabrous, light-colored when young, reddish when mature, column 1-2 mm, not twisted, junction with the awns inconspicuous;

awns (7)10-15(22) mm, subequal, usually horizontally spreading or curving downward, not disarticulating at maturity;

anthers 3, about 3 mm, reddish-brown.

2, usually longer than the florets, usually acute or acuminate;

florets terete or laterally compressed, with well-developed calluses;

lemmas 1- or 3-veined, more or less coriaceous, with a germination flap, lemma margins overlapping at maturity and concealing the paleas, apices evidently 3-awned;

awn bases often forming a column, lateral awns occasionally reduced or absent;

paleas less than 1/2 as long as the lemmas;

lodicules usually present, 2, free, membranous, glabrous, heavily vascularized;

anthers 1-3;

ovaries glabrous;

haustorial synergids absent;

styles 2, free to the base but close.

4-5 mm, chestnut brown.

usually fusiform, falling with the lemma and palea attached;

hila short or long, linear;

endosperm hard, without lipid;

starch grains compound;

embryos small or large relative to the caryopses;

epiblasts absent;

scutellar cleft present or absent;

mesocotyl internode elongated;

embryonic leaf margins meeting, x = 11, 12.

= unknown.