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.

usually erect, not compressed.

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;

ligules of hairs, or membranous and, usually, ciliate;

blades with vascular bundles separated by 2-6 radially arranged, tabular mesophyll cells and surrounded by a double sheath, cells of the inner sheath thick-walled, cells of the outer sheath with thinner cell walls and usually centripetal chloroplasts;

chloroplasts with well-developed grana.

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.

usually pyramidal, lax and diffuse, varying to contracted and condensed;

secondary branches usually present;

pedicels divergent to more or less appressed.

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.

ellipsoid to lanceolate, 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.

1/5 - 4/5 the length of the spikelets, 1-11-veined;

upper glumes and lower lemmas (5)7-15-veined;

lower florets usually sterile;

upper florets smooth, shining;

upper paleas with compound or compound and simple papillae towards the apices, x = 9.

C4 NAD-me type.

= 36, 54.