Flora of North America species comparison

10-75 cm, about 1 mm thick, simple or with erect basal branches;

nodes densely pilose, hairs ascending;

internodes glabrous or shortly pubescent distally.

30-150 cm tall, 3-7 mm thick, compressed, spongy, glabrous, decumbent and rooting at the lower nodes in shallow water;

nodes glabrous;

internodes glabrous, smooth.

longer than the internodes, green to purplish, hispid, margins sparsely ciliate;

ligules 0.5-1.5 mm;

blades 3-32 cm long, 1-7 mm wide, ascending to erect, linear, narrowing basally, flat or the margins involute, surfaces sparsely hirsute or pilose (rarely glabrous), hairs near the base papillose-based, margins prominent, apices acute.

usually shorter than the internodes, not keeled, glabrous or sparsely hispid distally;

ligules 1-4 mm;

blades 10-40 cm long, 5-15 mm wide, flat, glabrous, contracted basally, attenuate distally, apices acute.

5-45 cm long, 1-6 cm wide, at least 1/2 as long as the plants and 3 times longer than wide, open;

rachises glabrous;

primary branches usually alternate or subopposite, ascending to slightly divergent, secondary branches and pedicels attached to the distal 2/3;

secondary branches diverging;

pedicels 0.5-17 mm, ascending to appressed.

10-25 cm long, 5-17 cm wide, shortly exserted or included basally;

primary branches 4-12 cm, ascending to spreading, secondary and higher order branches confined to the distal 2/3, pedicels 1-4 mm, sharply 3-angled, ascending to appressed.

2.5 - 3.7 mm long, 0.6-1.1 mm wide, narrowly ovoid, glabrous, acute;

lower glumes 0.8-1.3 mm, 1/3 – 1/2 as long as the spikelets, acuminate;

upper glumes 2.3-3.3 mm, 7-9-veined, exceeding the upper florets by about 0.6 mm;

lower florets sterile;

lower lemmas 2.2-2.7 mm, exceeding the upper florets by about 0.6 mm, 7- or 9-veined, apices scabridulous, pointed;

lower paleas absent;

upper florets 1.6-1.7 mm long, about 0.6 mm wide, usually smooth, usually pale, sometimes becoming dark at maturity.

3-4 mm long, 0.8-2 mm wide, lanceolate.

0.5-0.9 mm, 1/5 – 1/3 as long as the spikelets, rounded, glabrous, truncate, weakly 1-3-veined;

upper glumes and lemmas subequal, glabrous, 9-11-veined, veins prominent, apices acute to accuminate;

lower paleas about 2/3 as long as the lower lemmas;

lower florets sterile;

upper florets 2-2.7 mm, narrowly ellipsoid, smooth, shiny, yellowish.

= 18.

= 54.