Flora of North America species comparison

20-150 cm tall, 2-4 mm thick, erect or spreading, sometimes decumbent and rooting from the lower nodes, distal portion sometimes floating in shallow water.

30-100 cm tall, 3-6 mm thick, spongy, usually decumbent and rooting at the lower nodes.

glabrous, keeled;

ligules 5-15 mm;

blades 5-25 cm long, 3-10 mm wide, both surfaces smooth.

smooth, weakly keeled;

ligules 5-9 mm;

blades 10-15 cm long, 3-8 mm wide, abaxial surfaces smooth, adaxial surfaces of the midcauline leaves often papillose.

10-50 cm long, 2-3 cm wide;

branches 3-5 cm, paired or solitary, usually appressed to ascending, divergent at anthesis, with 1-4 spikelets;

pedicels 0.8-20 mm.

often racemes, sometimes panicles, 15-35 cm long, 1-2 cm wide, open at anthesis, bases often enclosed in the flag leaf sheaths at maturity;

branches 5.5-8 cm (absent in racemose plants), solitary or in pairs, appressed, most branches with 1-3 spikelets, the lower branches sometimes with more than 3;

pedicels 1.5-2.5 mm.

(15)18-39 mm long, 1.7-3.3 mm wide, cylindrical and terete, except slightly laterally compressed at anthesis, rectangular in side view, with 8-16 florets.

20-45 mm long, 2.5-3 mm wide, cylindrical and terete except slightly laterally compressed at anthesis, rectangular in side view, with 5-12 florets.

unequal, acute;

lower glumes 1.3-4.5 mm;

upper glumes 3-7 mm;

rachilla internodes 2-3 mm;

lemmas 6-8.5 mm, scabridulous, 7-veined, gradually tapering from near midlength to the narrowly acute (< 45°) or acuminate apices;

paleas 0.7-3 mm longer than the lemmas, keels winged, tips parallel, intercostal region truncate, often splitting, apices appearing bifid, with 0.4-1 mm teeth;

anthers 3, 1-2 mm.

1.3-3.9 mm;

upper glumes 2.7-5 mm;

rachilla internodes 1.9-2.5 mm;

lemmas 5.2-8 mm, midveins extending to within 0.1 mm of the apical margins, scabrous over and between the veins, prickles about 0.05 mm, apices acute, usually entire;

paleas from shorter than to 0.6(1.5) mm longer than the lemmas, keels winged, apices bifid, teeth 0.1-0.4 mm, parallel to convergent, sometimes crossing when dry;

anthers 1.5-3 mm, usually purple.

2-3 mm.

about 3 mm.

= 40.

= 40.