MONOEClA.— PENTANDRIA. 353 



4, A. spinosus : flowers pentandrous, in terminal com- 



pound racemes ; axils spiny. 

 HAB. Waste grounds. June — Aug. 0. Stem 

 branch., diffuse, mostly coloured. §. 



5. A. pumilus : flowers pentandrous, in axillary clus- 



ters ; leaves ovate, obtuse, emarginate, fleshy, 

 subrugose ; stem diffuse, smooth. 

 HAB. Sandy sea coast. Aug. 0. Stem and leav. 

 purplish; plant smooth. 



543. XANTHIUM. Clot-weed. Urticece. 



1. X. strumarium : stem unarmed, branching; leaves 



cordate, lobed, unequally serrate, scabrous, 3- 

 nerved ; fruit elliptical, armed with uncinate rigid 

 bristles ; horns straight, spreading. 



HAB. Old fields, &c. Sept. ©. Stem 2— 3 ft. 

 high ; leav. large ; fl. axill. 

 7. X. macrocarpon : stem unarmed, spotted; leave? 

 cordate, lobed, obscurely sinuate-dentate, sca- 

 brous, 3-nerved ; fruit oval, densely armed with 

 short rigid uncinate bristles ; horns incurved. 



HAB. Near salt water. Aug. 0. Stem purp.- 

 spotted ; fr. very large, woolly. 

 3. X. spinosum: spines ternate ; leaves 3-lobed. 



HAB. Waste places. Aug. 0. Stem 3 ft. high, 

 much branch. ; spin, long, yell.; fr. small. 



544. AMBROSIA. Hog-weed. Urticece. 



f , A. trifida : hairy, rough ; leaves 3-lobed, serrate, 

 with oval-lanceolate acuminate lobes ; fruit 6- 

 spined below the summit. 

 HAB. Along ditches, &c. Sept. ©. Stem 4— 6 

 ft. high; leav. very large; spik. long, axill. and 

 term. 



2. A. elatior : leaves bipinnatifid, nearly smooth ; pe- 



tioles ciliate ; racemes terminal, paniculate ; stem 

 virgate. 

 HAB. Fields. Sept. 0. Stem 1—3 ft. high, 

 pubes. when young ; seg. of leav. acute. 

 '•. A. artemisifolia : leaves bipinnatifid, hoary beneath, 

 the uppermost pinnatifid ; racemes by threes, tei> 

 minal ; branches fastigiate. 

 Gg2. 



