Flora of North America species comparison

25-95 cm, generally decumbent and rooting at the nodes.

annual, not woody, solid or hollow.

glabrous, extensively overlapping;

ligules 1-2 mm;

pseudopetioles 8-60 mm;

blades 7-30 cm long, 2-6.5 cm wide, narrowly elliptic to obovate, often acuminate, lacking intercostal fibrous bands, sometimes whitened beneath, lateral veins diverging from the midvein at a 4-8° angle.

mostly cauline, evidently distichous;

sheaths open;

auricles absent;

abaxial ligules absent;

adaxial ligules membranous, ciliate;

pseudopetioles prominent, twisted so the blades are resupinate;

blades with the lateral veins evident, straight, diverging obliquely from the central vein;

mesophyll nonradiate;

adaxial palisade layer absent;

fusoid cells well developed, large;

arm cells weakly to moderately developed;

Kranz anatomy not developed;

midribs complex; inflated interstomatal cells present;

bulliform cells poorly developed or absent;

stomates with parallel-sided to dome-shaped subsidiary cells;

bicellular microhairs absent;

papillae absent.

10-40 cm, sparsely flowered;

branches solitary, with uncinate hairs, usually tipped with a staminate spikelet.

panicles, rachises and branches sometimes disarticulating, hairy, hairs uncinate.

unisexual, with 1 floret, mostly in staminate-pistillate pairs on short branchlets, some pistillate spikelets solitary.

hila subequal to the caryopses, linear;

endosperm hard, without lipid;

embryos small;

epiblasts present;

scutellar cleft present but short;

mesocotyl internode absent;

embryonic leaf margins overlapping, x = 12.

spikelets 2.5-3.5 mm, on 4-11 mm pedicels, subtending the pistillate spikelets, purple;

lower glumes 1-2 mm;

upper glumes 1.5-3.2 mm, 1- or 3-veined;

lemmas 2.5-3.5 mm;

paleas about 3/4 the length of the lemmas;

anthers 0.9-1.1 mm.

spikelets smaller than the pistillate spikelets, short- to long-pedicellate;

glumes 1-2, membranous, shorter than the floret;

lodicules absent or 3 and minute, elliptic, glabrous, veinless;

anthers 6.

spikelets 7.5-12 mm, diverging slightly from the branches;

glumes brown;

lower glumes 5-7 mm, 5-7-veined;

upper glumes 6-8 mm, 3-5-veined;

lemmas 7.5-12 mm, linear-oblong, abruptly short-beaked, with uncinate hairs nearly to the base;

paleas equaling the lemmas.

spikelets sessile or shortly pedicellate;

glumes 2, shorter than the floret;

lemmas tubular or inflated, covered wholly or in part with uncinate hairs, unawned;

paleas well developed;

lodicules absent;

ovaries glabrous, without an apical appendage;

styles 1, with 3 branches.

= 24.