550 SYNGENESIA. 



This Order is, still more evidently than the last, 

 analogous to double flowers of other Classes. Ac- 

 cordingly, Coreopsis lii ihe very same genus SisBidens, 

 only furnished with unproductive radiant florets. C. 

 bidens of Linnaeus is the same species as in B. cer- 

 nua ; C corojmta is his B. frondosa ; and C. leucan- 

 tha^ B. pilosa. Some species of Coreopsis indeed 

 have nev^er been found without rays. Linnaeus ex- 

 presses his difficulties on this subject in Phil. Bof. 

 sect. 209, but seems inclined to unite the two genera. 

 A similar ambiguity occurs between Gorteria and 

 Atractylis, Relhania (of the last Order) and Athana- 

 sia, and in some degree between Centaurea^ Engl 

 Bat. t. 278, 1678, 56, 8cc., and Cardmis, or Serra- 

 tula ; only the scales of the calyx of Centaurea gen. 

 crally keep that genus distinct. 



I should be much inclined to abolish this Order. 

 Those of its genera which have rudiments of pistils in 

 their radiant florets, as Rudbeckia and Helianthus^ 

 would very commodiously range with their near rela- 

 tions in Polygamia superjiua, nor are we sure that 

 such radiant florets are in all circumstances abortive, 

 neither can a student often know whether they are so 

 or not. It does not follow, from what has just been 

 observed, that the presence of radiant florets, whether 

 abortive or not, can never aflford a generic character, 

 provided there be no corresponding genus without 

 them. This must be determined by experience and 

 observation. They are indeed to be considered as a 

 verv secondary mark, the most essential in this Class 

 being derived from the receptacle, crown of the seed, 



