Flora of North America species comparison

20-80 (100) cm tall, (1.5)2-3.5 mm thick, not or only slightly spongy, sometimes rooting at the lower nodes.

usually hollow, sometimes solid.

smooth to scabridulous, keeled, sometimes weakly so;

ligules 1-4 mm, usually rounded, sometimes acute to mucronate, erose-lacerate;

blades 12-30 cm long, 2-6 mm wide, abaxial surfaces smooth or scabridulous, adaxial surfaces scabridulous to scabrous.

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.

6-25 cm long, 2.5-21 cm wide, pyramidal, open, nodding;

branches 5-13 cm, straight to lax, lower branches usually strongly divergent to drooping at maturity, sometimes ascending, with 15-50 spikelets, these often confined to the distal 2/3;

pedicels 0.5-7 mm.

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.

1.8-4 mm long, 1.2-2.9 mm wide, laterally compressed, oval in side view, with 3-7 florets.

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.

ovate, 1-1.5 times longer than wide, narrowing from midlength or above, veins terminating below the apical margins, apices often splitting with age;

lower glumes 0.5-1.2 mm, rounded to obtuse;

upper glumes 0.6-1.2 mm, acute or rounded;

rachilla internodes 0.1-0.6 mm;

lemmas 1.2-2 mm, ovate in dorsal view, veins raised, scabridulous over and between the veins, apices acute, prow-shaped;

paleas slightly shorter than to equaling the lemmas, lengths 1.5-3 times widths, keeled, keels not winged, tips pointing towards each other, apices narrowly notched between the keels;

anthers 2, (0.2)0.4-0.6 mm, purple or yellow.

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.

0.5-2 mm.

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.

= 20 [reports of 28 are questionable].