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.

50-300 cm tall, 2-4 mm thick, often compressed, erect or ascending, hard, becoming almost woody;

nodes swollen, glabrous or pubescent;

internodes glabrous, glaucous.

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.

not keeled, shorter than or equal to the internodes, glabrous or the lower sheaths at least partially pubescent, hairs papillose-based;

ligules 0.3-1.5 mm;

blades 10-60 cm long, 3-20 mm wide, elongate, flat, abaxial surfaces and margins scabrous, adaxial surfaces occasionally pubescent near the base, with prominent, white midveins, bases rounded to narrowed.

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.

10-45 cm, to 1/2 as wide as long, open or somewhat contracted, with many spikelets;

branches 4-12 cm, opposite or alternate, ascending to spreading;

pedicels 0.3-2.5 mm, scabridulous to scabrous, appressed to diverging less than 45° from the branch axes.

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.

2.4-3.4 mm long, 1-1.3 mm wide, ellipsoid-lanceoloid to narrowly ovoid, often purplish, glabrous, acute.

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.

1.4-2.2 mm, 1/3 – 1/2 as long as the spikelets, 3-5-veined, obtuse;

upper glumes and lower lemmas subequal, glabrous, 5-9-veined, margins scarious, acute;

lower florets staminate;

upper florets 1.8-2.8 mm long, 0.9-1.1 mm wide, smooth, lustrous, acute.

= 36, 54.

= 18, 36.