Flora of North America species comparison

annual, 20-500 cm tall, aerenchymatous, sometimes floating.

to 3.3(5) m, erect, decumbent, or prostrate, sometimes rooting at the lower nodes, aerenchymatous, emergent or immersed, branched or unbranched.

aerenchymatous;

auricles present or absent;

ligules membranous or scarious, sometimes absent;

pseudopetioles sometimes present;

blades with parallel veins, cross venation not evident;

abaxial blade epidermes with microhairs and transversely dumbbell-shaped silica bodies;

first seedling leaf without a blade.

cauline and basal;

sheaths open, lower sheaths often slightly inflated, upper sheaths not inflated;

auricles usually present;

ligules membranous, often veined;

pseudopetioles absent;

blades linear to narrowly lanceolate, flat, margins smooth or scabridulous.

usually panicles, sometimes racemes or spikes;

disarticulation below the spikelets, not occurring in cultivated taxa.

terminal panicles;

disarticulation above the glumes, beneath the sterile florets in wild taxa, spikelets of cultivated taxa not disarticulating.

laterally compressed or terete, with 1 bisexual or unisexual floret, sometimes with 2 sterile florets below the sexual floret, these no more than 1/2 (9/10) the length of the fertile floret;

unisexual spikelets in the same or different panicles;

rachillas not prolonged.

bisexual, laterally compressed, with 3 florets, lower 2 florets sterile, terminal floret functional.

absent or highly reduced, forming an annular ring or lobes at the pedicel apices;

sterile florets 1/8 – 1/2 (9/10) as long as the spikelets;

fertile lemmas 3-14-veined, membranous or coriaceous, apices entire, unawned or with a terminal awn;

paleas similar to the lemmas, 3-10-veined, 1-keeled;

lodicules 2;

anthers usually 6(1-16);

styles 2, bases fused or free, stigmas linear, plumose.

absent or reduced to lobes at the pedicel apices;

sterile florets glumelike, 1.2-10 mm, 1/8 - 1/2 (9/10) as long as the spikelets, linear or subulate to narrowly ovate, coriaceous, 1-veined, acute to acuminate;

functional florets: calluses usually inconspicuous and flat to rounded, sometimes conspicuous and stipelike, glabrous;

lemmas coriaceous or indurate, with vertical rows of tubercles separated by longitudinal furrows, 5-veined, keeled, margins clasping the margins of the paleas, apices obtuse or acute to acuminate, awned or unawned;

paleas with surfaces similar to the lemmas, 3-veined, unawned;

lodicules 2;

anthers 6;

styles 2, bases fused or not, stigmas laterally exserted, plumose.

laterally compressed;

embryos usually ¼ - 1/3 as long as the caryopses;

hila linear, x = 12.

usually caryopses, sometimes achenes, ovoid, oblong, or cylindrical;

embryos of the F+FP or F+PP type, small or elongate, with or without a scutellar tail;

hila usually linear, x = 12, 15, 17.