MONOECIA POLYANDRIA. 437 



varicate, inferior ones sterile and longer than the petiole, u^iper ones 

 fertile, elongate, stem very hispid, stinging. 



HAB. Shady rocks. Aug. Sept. 7J. ; stem 46 feet high, fibres 

 tough. 



PENTANDRIA. 

 376. AMARANTHUS. 



k. hybridus : flowers pentandrous ; racemes decompound, erect, crowd- 

 ed ; leaves ovate-lanceolate. 



HAB. Waste grounds. Aug. j stem 2 3 ft. high ; racem. large, 

 thick. . 



377. XANTHIUM. Clot-weed. 



X. strumarium : stem unarmed, branching ; leaves cordate, lobed, une- 

 qually serrate, scabrous, 3-nerved ; fruit elliptical, armed with unci- 

 nate rigid bristles ; horns straight, spreading. 



HAB. Old fields, &c. Sept. fv) ; stem 2 3 feet high ; leaves large ; 

 ft. axill. 



378. AMBROSIA. Hog-weed. 



A., trifida : hairy, rough ; leaves 3-lobed, serrate, with oval-lanceolate 

 acuminate lobes ; fruit 6-spincd below the summit. 



HAB. Alongdiches, &c. Sept. ; stem 4 6 feet high; leaves 

 very large ; spik. long, axill. and term. 



A . elatior : leaves bipinnatifid, nearly smooth ; petioles ciliate ; ra- 

 cemes terminal, paniculate ; stem virgate. 



HAB. Fields. Sept. <v> ; stem 1 3 feet high, pubes. when young ; 

 seg. ofleav. acute. 



HEXANDR1A. 

 379. ZIZANIA. Wild rice. 



Z. aquatica : panicle pyramidal, divaricate and sterile at the base, 

 spiked and fertile above ; pedicels of the flower clavate ; awns long 

 seed linear. 



HAB. In water. Aug. _1|.; culm 4 8 feet high, thick; leav. broad 

 lin. : ft. decid. 



~ 



POLYANDRIA. 



380. MYRIOPHYLLUM. Water milfoil. 



M. spicatum : sterile flowers in interrupted leafless spiked whorlb 



