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.

20-210 cm, stout, not woody;

nodes puberulent;

internodes usually with papillose-based hairs, sometimes nearly glabrous, not succulent.

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.

numerous;

sheaths terete, densely pilose, with papillose-based and caducous hairs;

ligules membranous, ciliate, cilia 1-3 mm;

blades 15-40 cm long, 7-25 mm wide.

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.

6-20 cm long, 4-11 cm wide, included or shortly exserted at maturity, dense;

branches stiff, appressed to spreading, spikelets solitary, confined to the distal portions;

pedicels 1-9 mm, scabrous and sparsely pilose.

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.

4-6 mm, ovoid, usually glabrous.

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.

2.8-3.6 mm, 1/2 - 3/4 as long as the spikelets, 5-7-veined, veins scabridulous distally, apices attenuate;

upper glumes 4-5.1 mm, slightly exceeding the upper florets, 11-13(15)-veined, veins scabridulous distally;

lower florets sterile;

lower lemmas 4-4.8 mm, slightly exceeding the upper florets, 9-13-veined, veins scabridulous distally;

lower paleas 1.2-1.6 mm, 1/2 or less the length of the upper florets, truncate to bilobed;

upper florets 3-3.8 mm long, 2-2.5 mm wide, smooth or striate, more or less shiny, stramineous to orange, red-brown, or blackish, persisting in the spikelets or disarticulating at maturity.

= 36, 54.

= 36, 40, 42, 49, 54, 72.