3M 3I0N0ECIA.— POLtANDIllA. 



HAB. Fields. Aug.— Sept. 0. Stem 4 ft. high ; 

 leav. subpubes. above, whitish beneath, 

 4. A. heterophylla : leaves of the stem pinnatifid, sub- 

 dentate, petiolate ; uppermost ones lanceolate, 

 sessile ; petioles conspicuously ciliate ; racemes 

 terminal, solitary ; stem paniculate. 



HAB. Banks of rivers and ditches. Aug.— Sept 



HEXANDRIA. 



545. ZIZANIA. Wild rice. Gramineu. 



\. Z. aquatica : panicle pyramidal, divaricate and ste 

 rile at the base, spiked and fertile above ; pedicels 

 of the flower clavate ; awns long ; seed linear. 



HAB. In water. Aug. U>. Culm 4 — 8 ft. high) 

 thick; leav. broad-lin. ; Jl. decid. 

 2. Z. miliacea : panicle effuse, pyramidal ; glumes 

 with short awns ; sterile and fertile florets inter- 

 mixed ; style 1 ; seed ovate, smooth ; leaves glau- 

 cous. 



HAB. In water. U. Culm G ft. high; joint? 

 smooth ; leav. broad, perennial. 



546. HYDROCHLOA. Graminea. 



H. fluitans. 



HAB. Lakes. July. U. Floating; culm long, 

 slender; leav. flat ; spik. solit., axill., setaceous; 

 glumes awnless. 



POLYANDRIA. 



5*7. CERATOPHYLLUM. Hornwort. Uncertain.. 



C. demersum : fruit armed with 3 spikes, 



HAB. Underwater. July. U . Stem long, slend,. 

 much branch.; leav. verticill. 



548. MYRIOPHYLLUM. Water milfoil. Haloragex, 



f, M. spicatum: sterile flowers in interrupted leaflet 

 spiked whorls. 



