Flora of North America species comparison

30-130 cm, terete to slightly compressed.

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.

laterally compressed, glabrous or sparsely to densely pilose or villous, especially at the summit;

ligules less than 0.5 mm, membranous, erose, often brownish;

blades 10-50 cm long, 4-12 mm wide, erect, adaxial surfaces pilose at least basally, glabrous or pilose abaxially.

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.

10-40 cm, 1/4 - 2/3 as wide as long, well-exserted at anthesis;

branches relatively few, stiffly spreading or ascending; ultimate branchlets 1-sided;

pedicels 0.1-3 mm, scabridulous to scabrous, 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.

2.3-3.9 mm, narrowly ellipsoid to ovoid, usually subsessile, usually pale to yellowish-green, glabrous, often falcate and gaping at the apices, rarely lanceolate, densely crowded on short, appressed branchlets, set obliquely on short pedicels.

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

A-A as long as the spikelets, 3-veined, keels scabrous, apices acute;

upper glumes and lower lemmas subequal, keeled, beaked, usually gaping at the apices;

lower florets sterile;

lower paleas subequal to the lower lemmas;

upper florets 1.5-2.2 mm long, about 1 mm wide, 2/5 – 3/4 as long as the spikelets, apices with a tuft of minute, thick hairs;

upper lemmas thick, stiff, clasping the upper paleas throughout their length.

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, 36.

= 54.