Flora of North America species comparison

5-200 cm tall, 0.4-3 mm thick, decumbent to erect, commonly geniculate to ascending, rooting at the lower nodes when in water, simple to divergently branched from the lower and middle nodes, usually succulent, slightly compressed, glabrous;

nodes usually swollen, sometimes constricted on robust plants, glabrous;

internodes glabrous, shiny, pale green to purplish.

60-130 cm, thick, glabrous, rooting profusely at the lower nodes;

nodes glabrous, often with a dark green band.

compressed, inflated, sparsely pubescent near the base, elsewhere mostly glabrous, sparsely pilose, or hispid, hairs sometimes papillose-based, margins or throat ciliate, with papillose-based hairs;

ligules 0.5-2 mm;

blades 10-65 cm long, 3-25 mm wide, glabrous or sparsely pilose, often scabrous near the margins, midribs stout, whitish.

usually shorter than the internodes, glabrous, prominently veined;

ligules 0.5-1.5 mm;

blades 15-40 cm long, 7-25 mm wide, tapering from midlength, flat, both surfaces glabrous, bases subcordate, margins scabrous to smooth, widest at the base, apices acute.

4-40 cm, diffuse, lax, with a few spikelets;

branches to 15 cm, alternate or opposite, occasionally verticillate, ascending to spreading, stiff, scabrous;

pedicels 1-6 mm, sharply 3-angled, scabrous, expanded to cuplike apices, appressed mostly to the abaxial side of the branches.

10-40 cm long, 7-20 cm wide, open, with straight, rigid rachises;

branches whorled, stiffly ascending, with short, appressed, higher order branches; ultimate branchlets 1-sided, with solitary spikelets or small clusters of spikelets;

pedicels 0.1-1.5 mm.

1.8-3.8 mm long, 0.7-1.2 mm wide, ellipsoid to narrowly ovoid, light green to red-purple, glabrous, acute to acuminate.

5.5-7 mm long, about 1 mm wide, narrowly lanceoloid, glabrous.

spreading apart at maturity, keeled, prominently veined, scabrous along the midveins;

lower glumes nearly as long as the lower lemmas;

upper glumes and lower lemmas 3-veined, spreading, greatly exceeding the upper florets, lower lemmas longer than the upper glumes, arcuate;

lower florets sterile;

lower paleas thin;

upper florets 1.9-2.2 mm, less than 1/3 as long as the spikelets, obovoid, lustrous, pale to brownish, acute, often short-stipitate.

0.6-1.2 mm, 1/4 - 1/3 as long as the spikelets, 0-3-veined, obtuse to acute;

upper glumes and lower lemmas similar, exceeding the upper florets by 0.3-0.6 mm, 7-9-veined;

lower paleas vestigial to almost as long as the lower lemmas;

lower florets sterile;

upper florets 1.4-2.5 mm long, 0.7-1.1 mm wide, narrowly ellipsoid, smooth, shiny, stramineous to nigrescent, with pale veins.

= 36, 54.

= 40.