Mr. T. Smith on certain Species of Cardans and C 'atcifj 593 



Mr. Brown in his Observations on the Composite, inserted in 

 the 12th volume of the Transactions of this Society*, announced 

 many more instances of this remarkable circumstance: it forms 

 a part of his character of the genus Bacekaru, which Richard and 

 Jussieu had previously proposed to limit to such species as were 

 dioecious, and which thus comprehending Molina of the flora 

 Peruviana, contains many species. The plants forming two of 

 the new genera there proposed (Petrobium and BrachyUtna) he 

 has ascertained to be dioecious ; another genus, Piptocarpka, be 

 suspects to be so; and the dioecious Gnapkaiiumt (to which he 

 shows that ffiargaritaccum must be added) arc also thrown into a 

 separate genus. 



It will be observed, that the greater part of the genera men 

 tioned belong to orders which have florets of different sexes in 

 the same capitulum ; in such the prevalence of one sort of florel 

 in all the capitulaof a plant to the exclusion nt the other is a cir- 

 cumstance not so unexpected as in the order Syngenesia JEquatis, 

 where all are hermaphrodite ; to this, however, Petrobium and 

 Brachylcena are referable : and Mr. Brown's description (in the 

 same paper) of the separation of the sexes in Scrrdtula titutona, 

 led me to notice the same circumstance in Serratula. or, as it is 

 now most frequently called, Cnicus arvensis, and in some other 

 species of the genera Carduus and Cnicus, all of which were sup- 

 posed to have hermaphrodite flowers only. 



So long ago as the year 1807 1 had observed that there were 

 many plants of Serratula tinctoria in which the anthene wire en- 

 tirely abortive; but finding others in which all the organs were 



conclusion to the above, and considers the two plants as distinct species. His words 

 are : " Les styles du Tussilago hybrida different assez du ceux du T. Petasitct, j>our de- 

 montrer, independamment de plusieurs autres argument, que cea deux plantes n'ap- 

 partiennent point a la meme espece, comme l'ont cru tres mal-a-propo? quelques bo- 

 tanistes modernes." Journal de Physique, torn, lxxvi. p. 191. 



apparently 



