Flora of North America species comparison

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

1-4 m, erect or decumbent, sometimes rooting at the nodes.

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.

basal and cauline;

sheaths open, somewhat laterally compressed;

ligules scarious;

pseudopetioles absent;

blades flat or folded at the base, lanceolate.

usually panicles, sometimes racemes or spikes;

disarticulation below the spikelets, not occurring in cultivated taxa.

terminal panicles, staminate and pistillate spikelets on the same branches, staminate spikelets proximal, pistillate spikelets distal;

disarticulation beneath the spikelets;

pedicel apices cupulate.

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.

unisexual, laterally compressed to subterete, lemma margins not clasping the paleas, with 1 floret.

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 glabrous.

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.

achenes, ellipsoid or obovoid, beaked by the persistent style base;

pericarps shell-like, partially free from the seed, smooth, coriaceous or crustaceous;

seeds oblong, subterete, or 2-angled;

embryos basal;

hila linear, x = 12.

lemmas membranous, 5-7-veined, acuminate or terminally awned;

paleas similar to the lemmas, 3-veined;

lodicules 2;

anthers 6.

lemmas membranous, 7-veined, terminally awned;

paleas similar to the lemmas, 3-veined, awned or unawned;

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