which appear to be dioecious, 509 



for although, when the stigma of the female tiower is compared 

 with that part in the antheriferous one, a much greater develop- 

 ment is perceived in the female, still in the former it is appa- 

 rently sufficiently developed for the purposes «.i impregnation : 

 hence it is not possible, from seeing a few plants with perfect an- 

 therae, to say whether the species is dioecious or not ; it can onlj 

 be determined by an examination of numerous specimen-. 



There is another source of error : In Cnicus prat cutis the an- 

 theriferous plants which were growing near the females had 

 when gathered the appearance of being males; bat having kept 

 them for some days and noticed the progress of tin- de\ elopment 

 of the different parts of the flower, it was teen that, irhen the 

 pollen of a particular tiower was cntireK dispersed, the stigma 

 became developed nearly as much as in the female tiower, al 

 though while the style remained covered with pollen it was 

 merely indicated by a line, which induced the idea that t la- 

 plant was a male : I afterwards found also the antheriferous ca- 

 pitula impregnated, except the rlorets of the ray, the stigmas of 

 which were not developed nor the ovaria impregnated : whether 

 this is constantly the case, remains for future inquin 



Neither in C7iicus palustris nor in acaulis have I ascertained 

 that male plants exist ; in palustris, from the numerous speci- 

 mens examined, I should conclude that they do not, and that 

 this plant therefore consists of hermaphrodites and females, the 

 former being the most numerous. 



In another plant of the Carduacea, equally common with 

 Cnicus arvensis, 1 have also found female plants; this is the 

 Centaurea nigra ; but I have not found any that can be called 

 males, as those plants in which the anthers are perfect have per- 

 fect seeds. 



The female and hermaphrodite (as it must be called here) dif- 

 fer as the male and female do in Cnicus arvensis. The female 



4 u 2 florets 



