-40 DICOTYLEDONS.- COMPOSITE. Artemisia. 



leaves pinnatifid rough ish, the segments lanceolate acute, p. 249. 

 Pastures and fields. 



Div. III. CORYMBIFERJ:. Floret s all tubular, erect and paral- 

 lel, or ii'iih those of the circumference ligulate. 



1. DISCOIDEI. Florets tubular, erect, crowded, parallel, nearly 

 plane at the top. 



20. BIDENS. 



Involucre of many leaves, with many foliaceous Iracteas at the 

 base. Receptacle plane, chaffy. Cor. sometimes radiant. Pe- 

 ricarps crowned with from 2 5 persistent awns, which are 

 rough with minute deflexed bristles.. 



1 . B. cernua, flowers drooping, bracteas lanceolate entire (longer 

 than the involucre), leaves lanceolate serrated undivided, bris- 

 tles of the pericarp about 4 erect, p. 238. Sides of ditches. 



2. B. tripartita, leaves tripartite, leaflets lanceolate deeply ser- 

 ratedj bristles of the pericarp 2 3. p. 238. Marshes. 



21. EUPATORIUM. 



Involucre imbricated^ oblong. Floret stew. Receptacle naked. 

 Pappus rough. 



1. E. cannabinum, leaves opposite subpetiolate tri-quinque-par- 

 tite, their segments lanceolate deeply serrated, p. 238. Ri- 

 ver -banks. 



22. TANACETUM. 



Involucre hemispherical, imbricated. Receptacle naked. Flo- 

 rets of the ray trifid, obsolete^ sometimes wanting. Pericarps 

 crowned with a membranous margin or pappus. 



1. T. vulgare, leaves bipinnatifid inciso-serrate. p. 239. Bor- 

 ders ofjields. 



23. ARTEMISIA. 



Involucre ovate or rounded, imbricated. Receptacle naked (or 

 downy, Sin.). Florets of the ray subulate. Pericarps crowned 

 with a membranaceous pappus. 



1. A. maritime, " leaves downy pinnated, the uppermost undi- 

 vided, racemes drooping, receptacle naked., flowers oblong ses- 

 sile/' Sm. p. 239. Sea-shore. 



2. A. gallica, " leaves downy pinnated, radical ones capillary, 

 upper ones undivided, racemes erect, receptacle naked, flowers 

 oblong, "Sm. p. 239. Sea-shore. 



3. A. Absintliium, leaves bi-tripinnatifid clothed with short silky 

 down, segments lanceolate, flowers hemispherical drooping, 

 receptacle hairy. /;. 239. Way-sides* 



4. A. vulgar is, leaves pinnatifid, their- segments cut downy be- 

 neath, flowers somewhat raccmed ovate, receptacle naked, 

 p. 240. Waste places. 



