Flora of North America species comparison

10-40 cm, highly branched above the base in age;

internodes glabrous or pubescent, sometimes nearly lanose.

annual, erect, solid or hollow, usually unbranched.

cauline;

sheaths shorter than the internodes, glabrous or puberulent;

collars glabrous or pubescent at the sides;

ligules 0.5-1 mm;

blades usually less than 6 cm long, 0.5-1 mm wide, pale green, involute, glabrous or puberulent abaxially.

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 or racemose, 5-10 cm long, 1-2 cm wide, with few spikelets;

rachis nodes glabrous or with straight hairs;

primary branches 1-2 cm, appressed, without axillary pulvini.

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

disarticulation above the glumes.

appressed.

bisexual, with 1 floret;

rachilla extension absent.

unequal, 1-2-veined;

lower glumes 4-10 mm;

upper glumes 7-15 mm;

calluses about 1 mm;

lemmas 5-7 mm, purple or mottled, junction of the lemma and awns evident;

awns twisted together basally into a 4-26 mm column, free portions 12-50 mm, those of the central and lateral awns similar in length, curved to arcuate basally, straight and divergent distally, disarticulating at the base of the column at maturity;

anthers 3, about 2 mm long.

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.

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.

= 22.