Flora of North America species comparison

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

10-100+ cm, erect or prostrate, sometimes rooting at the nodes, branched, emergent or immersed.

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;

sheaths open, not inflated or somewhat inflated;

ligules hyaline;

pseudopetioles present or absent;

blades flat, linear to lanceolate or narrowly elliptic, glabrous, pubescent, or scabrous.

usually panicles, sometimes racemes or spikes;

disarticulation below the spikelets, not occurring in cultivated taxa.

panicles, racemes, or spikes, exserted or enclosed, staminate and pistillate spikelets usually in separate inflorescences, pistillate inflorescences at the lower or middle nodes, staminate inflorescences usually terminal;

disarticulation below 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.

unisexual, laterally compressed to subterete, 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;

lemmas and paleas subequal, ovate or lanceolate, membranous or hyaline, unawned;

lodicules 2.

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, ovoid, ellipsoid, or subglobose, beaked by the persistent style bases;

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

seeds ovoid to subglobose;

embryos basal;

hila linear, x = 12.

lemmas and paleas obscurely few- to several-veined;

anthers 6-16.

lemmas 5-14-veined, margins not clasping the margins of the paleas, unawned;

paleas 3-10-veined;

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