'244 DICOTYLEDONS. COMPOSITE. Achillea. 



35. PYRETHRUM. 



Involucre hemispherical, imbricated with scales whose larders 

 are membranous. Receptacle naked. Pericarps crowned with 

 a membranous margin. 



1. P. Parthenium, leaves petiolate flat bipinnate, the segments 

 ovate cut, peduncles branched corymbose, stem erect, involu- 

 cre hemispherical pubescent, p. 246. Waste places. 



2. P. inodorum, leaves sessile bipinnatifid with the segments ca- 

 pillary, stem branched spreading, pappus entire, p. 246. 

 Way -sides. 



3. P. marilimum, leaves bipinnatifid, the segments linear fleshy 

 awnless, stem diffuse branched, pappus lobed. p. 246. Sea- 

 coast. 



36. MATRICARIA. 



Involucre hemispherical or almost plane, imbricated with scales 



whose borders are membranous. Receptacle naked, almost 



cylindrical. Pappus none. 

 1. M. Chamomilla, leaves glabrous bipinnatifid the segments 



capillary, involucre nearly plane its scales obtuse, p. 246. 



Waste grounds. 



37. ANTHEMIS. 



Involucre hemispherical ; its scales nearly equal, their margins 

 scariose. Receptacle convex, chaffy. Pericarps crowned with 

 a membranous border or pappus. 



1. A. nobilisj leaves bipinnate, the segments linear subulate a 

 little downy, scales of the receptacle membranous scarcely 

 longer than the disk. p. 247. Waste places. 



2. A. arvensis, leaves bipinnatifid, their segments linear lanceo- 

 late pubescent, receptacle conical, its scales lanceolate, pericarps 

 crowned with an entire pappus, p. 247. Corn-Jields. 



3. A. Gotula, leaves bipinnatifid glabrous, their segments subu- 

 late, receptacle conical, its scales setaceous, p. 247. Waste 

 places. 



4. A. (rnctoria, leaves bipinnatifid serrated downy beneath, stem 

 erect branched subcorymbose. p. 247. Road-sides. 



38. ACHILLEA. 



Involucre ovate, imbricated, unequal. Receptacle plane, chaffy. 

 Florets of the ray 5 10, roundish-obcordate. Pericarps 

 naked. 



* Flowers white, or rarely reddish. 



1. A. Ptarmica, leaves linear lanceolate acuminate sharply ser- 

 rated, p. 248. Pastures. 



2. A. Mitlefolium, leaves bipinnate slightly hairy, their segments 

 linear toothed acute, stems furrowed, p. 248. Way-sides. 



