45. coMposiiJ!]. 183 



angular, not winged. Pappus 0, or a slight membranous 

 border. 



tt Receptacle without scales. Heads discoidal. 



(18.) 19. Aetemisia. F1. of disk perfect ; of the ray fern., 

 slender, in 1 row; or aU herm. and tubular. Involucre 

 roundish. PhylL imbricate. Receptacle naked or hairy. 

 Fr. obovate, with a small epigynous disk, without pappus. 



(19.) 20. Tanacbtum. F1. as in Artemisia. Involucre he- 

 mispherical. PhyH. imbricate. Receptacle naked. Pr. 

 oblong, angular, with a large epigynous dish (as broad as 

 the fruit), crowned with a slight membranous border. 



ttt Receptacle scaly. Pappus scale-like. 



(20.) 24. Gaiinsoga. Heads radiant. Fl. of ray fem., 

 ligulate, in one row ; of the disk perfect, tubular. Recep- 

 tacle conical. PhyU. 4 — 6, broad, ciliate, in one row. Fr. 

 prismatic, with a pappus of oblong scales. 



tttt Receptacle scaly throughout. Pappus 0. 



(21.) 15. Anthbmis. Heads radiant. Fl. of the ray fem., 

 or neuter, ligulate, in 1 row ; of the disk perfect, tubular. 

 Receptacle convex or conical. PhyU. imbricate, of few 

 rows. Fr. terete, or bluntly tetragonal, without pappus, 

 but with a more or less prominent margin. 



[Anactclus. Ft. compressed, winged at the edges. Other- 

 wise like Anthemis.~\ 



(22.) 14. Achillea. Heads radiant. Fl. of the ray fem., 

 ligulate, short ; of the disk perfect, tubular ; tube plane- 

 compressed, %-winged. Receptacle nearly flat, afterwards 

 often narrow and lengthened. Inv. ovate or oblong. PhyU. 

 imbricate. Fr. compressed, without pappus. 



(23.) 18. DiOTis. Heads discoidal. Fl. aU perfect, tubular ; 

 tube compressed, with 2 auricles at the base. Receptacle 

 convex, with concave downy-topped scales. Inv. bellshaped. 

 PhyU. imbricate. Fr. compressed, crowned with ths per- 

 sistent auricled tube of the cor. ; pappus 0. 



C. Pappus of 2 — 5 stiff' bristles. Receptacle scaly throfughout. 



(24.) 2.3. BiDENS. Heads discoidal, sometimes radiant. Fl. 

 (of the ray neuter, ligulate;) of the disk herm., tubular. 

 Receptacle flat. Phyll. in 2 rows, outer row spreading. 



