240 DICOTYLEDONS, — C0MP0S1T.5:. Artemisitt. 



leaves pinnatifid roughishjthe segments lanceolate acute, p. 249. 

 — Pastures and fields. 



Div. III. CoRYMBiFER.'E. FioTcts all tuhulor, erect and paral- 

 lel, or iviih those of the ckctmijercnce Ugulate. 



I. DiscoiDEi. Florets tubular, erect, crowded, parallel, nearhj 

 plane at the top. 



20. BIDENS. 



Involucre of many leaves, with many foliaceous hracteas at the 

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

 ricarps crowned with from 2 — 5 persistent aiuns, which are 

 rough with minute deflexed bristles. 



1. B. ierviia, flowers drooping, hracteas 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- 

 rated, bristles of the pericarp 2 — 3. p. 238. — Marshes. 



21. EUPATORIUM. 



Involucre imbricated, oblong. Florets few. Receptacle naked. 



Pappus rough. 

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



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

 _. ver-lanks. 



22. TANACETUM. 



Involucre hemisphaerical, 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 iuciso-serrate. p. 239. — Bor- 

 ders of fields. 



23. ARTEMISIA. 



Involucre ovate or rounded, imbricated. Receptacle naked (or 

 downy, Sm.). F/orei5 of the ro?/ subulate. Pemarp 5 crowned 

 with a membranaceous pappus. 



1. A. '■.naritima, " leaves downy pinnated, the uppermost undi- 

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

 sile," Sin. p. 239. — Sea-shore. 



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

 upper ones undivided, racemes erect, receptacle naked, flowers 

 oblong, "Srn. p. 239. — Sea-shore. 



3. A. Absinthium, leaves bi-tripinnatind clothed with short silky 

 down, segments lanceolate, flowers hemisphaerical drooping, 

 receptacle hairy, p. 239. — IVay-sides. 



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

 neath, flowers somewhat racemed ovate, receptacle naked. 

 p. 240. — Waste places. 



