Flora of North America species comparison

15-80 cm, erect or the bases decumbent, terete or weakly compressed;

nodes terete, 0-1 exserted.

usually hollow, sometimes solid.

closed for 1/10 – 1/5(1/4) their length, terete, smooth or sparsely scabrous, glabrous, bases of basal sheaths glabrous, distal sheath lengths (1.2)1.5-9(20) times blade lengths;

ligules (1)1.5-4(5) mm, smooth or sparsely to moderately scabrous, apices obtuse to acute;

blades strongly to gradually reduced in length distally, 1.5-5 mm wide, flat and moderately thin to folded and moderately thick and firm, abaxial surfaces smooth, adaxial surfaces smooth or sparsely to moderately scabrous, primarily over the veins, apices narrowly prow-shaped, flag leaf blades (0.4)1-7(10) cm.

intra- and extravaginal.

distichous;

sheaths usually open to the base, varying to closed for nearly their full length;

auricles present or absent;

abaxial ligules absent;

adaxial ligules scarious or membranous, sometimes puberulent or scabridulous, usually not ciliate, cilia sometimes shorter than the base;

pseudopetioles rarely present;

blades usually linear, sometimes broadly so, venation parallel;

cross sections non-Kranz, mesophyll nonradiate, adaxial palisade layer absent, fusoid and arm cells usually absent;

midribs usually simple;

adaxial bulliform cells present;

stomates with parallel-sided subsidiary cells;

epidermes usually lacking bicellular microhairs, sometimes with unicellular microhairs, papillae usually absent, when present, rarely more than 1 per cell.

(2.5)4-12(18) cm, erect, usually narrowly lanceoloid, contracted, sometimes interrupted, infrequently loosely contracted, usually congested, with 25-100 spikelets;

nodes with 1-5 branches;

branches 1-9 cm, erect to infrequently ascending, rarely spreading, terete to weakly angled, smooth or the angles sparsely to moderately scabrous, with 3-24 spikelets.

usually terminal, panicles, spikes, or racemes, usually ebracteate;

disarticulation usually below the florets, sometimes below the glumes, at the rachis nodes, or at the inflorescence bases.

3.2-7 mm, lengths to 3.5(3.8) times widths, laterally compressed;

florets 2-7;

rachilla internodes smooth, sometimes sparsely puberulent.

usually bisexual, infrequently unisexual or mixed, usually laterally compressed or not compressed, occasionally dorsally compressed, with 1-30 sexual florets, distal floret(s) often reduced, infrequently spikelets with 1-2 reduced or staminate basal florets and a single terminal sexual floret.

lanceolate, distinctly keeled, smooth or sparsely scabrous;

lower glumes 3-veined;

calluses usually glabrous, infrequently webbed, hairs to 1/4 the lemma length;

lemmas 2.5-4.5 mm, lanceolate to narrowly lanceolate, distinctly to weakly keeled, keels and marginal veins short- to long-villous, lateral veins moderately prominent, glabrous or puberulent, intercostal regions usually glabrous, infrequently hairy, hairs to 0.3 mm, margins glabrous, apices acute or blunt;

palea keels scabrous, glabrous or short-villous at midlength, intercostal regions usually glabrous, sometimes puberulent to short-villous;

anthers 1.3-2.2 mm.

usually 2, upper or lower glumes sometimes absent, rarely both glumes absent;

lemmas without uncinate hairs, awned or not, awns single, basal to apical;

paleas usually well-developed, sometimes reduced or absent;

lodicules 2(3), usually lanceolate and broadly membranous distally, rarely truncate and fleshy, usually not veined or obscurely veined, sometimes distinctly veined, sometimes ciliate;

anthers (1, 2)3;

ovaries glabrous or sometimes hairy distally, sometimes with an apical appendage;

haustorial synergids absent;

styles (1)2 (-4), bases close together, sometimes fused.

hila linear, elliptic, ovate, or punctate;

endosperm usually hard, sometimes soft or liquid, with or without lipids, starch grains compound or simple;

embryos less than 1/2 the length of the caryopses;

epiblasts usually present;

scutellar cleft usually absent;

mesocotyl internode usually absent;

embryonic leaf margins overlapping, x = 7, 10.

= 56, 56+1, 56-58, 63, 64, 70, 76, 84, ca. 90, 95+-5, 100, 103.