Flora of North America species comparison

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

20-150 cm (occasionally longer in floating mats), erect or decumbent, often rooting at the nodes, 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.

equitably distributed along the culm;

sheaths open;

auricles absent;

ligules membranous;

pseudopetioles absent;

blades aerial, linear to broadly lanceolate, flat or folded, sometimes involute when dry.

usually panicles, sometimes racemes or spikes;

disarticulation below the spikelets, not occurring in cultivated taxa.

terminal panicles, usually exserted, axillary panicles sometimes also present;

disarticulation beneath the spikelets.

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, with 1 floret;

florets laterally compressed, linear to suborbicular in sideview.

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;

calluses not stipelike, glabrous;

lemmas and paleas subequal, chartaceous to coriaceous, ciliate-hispid or glabrous, tightly clasping along the margins;

lemmas 5-veined, obtuse or acute to acuminate, sometimes mucronate, usually unawned;

paleas 3-veined, unawned;

lodicules 2;

anthers 1, 2, 3, or 6;

styles 2, bases fused, stigmas laterally exserted, plumose.

laterally compressed;

embryos about 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.