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.

60-100 cm tall, 1.5-5 mm thick, often 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.

glabrous, keeled;

ligules 4-12 mm;

blades 9-25 cm long, 2-7 mm wide, often floating, abaxial surfaces smooth, adaxial surfaces of the midcauline leaves densely papillose, glabrous.

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.

18-40(50) cm long, 0.5-2(5) cm wide, arching, usually narrow, open at anthesis, bases often enclosed in the upper leaf sheath at maturity;

branches 5-10(15) cm, usually 1-3(5) per node, usually appressed to strongly ascending, occasionally spreading, longer branches with 3-6 spikelets;

pedicels 1.2-5 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.

9-22 mm long, 0.8-2.5 mm wide, cylindrical and terete, except at anthesis when slightly laterally compressed, rectangular in side view, with 8-12 florets.

elliptic, apices rounded to obtuse, sometimes erose;

lower glumes 1.2-2.2 mm;

upper glumes 2-3.8 mm, rounded;

rachilla internodes 0.6-3.5 mm;

lemmas 2.7-5.4 mm, veins raised, scabridulous or smooth, intercostal regions usually smooth, sometimes scabridulous, midvein terminating about (0.1)0.2 mm short of the apical margin, apices usually acute, sometimes obtuse, entire or almost so;

paleas usually shorter than to equaling the lemmas, sometimes exceeding them by up to 0.5 mm, keels narrowly winged, apices bifid, teeth to 0.2 mm, parallel to weakly incurved;

anthers 3, 0.4-1.5 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.

1.2-2 mm.

= 40.

= 20.