16 Mr. T. Smith on cerlain Species of 



pears much larger than the female. The part of the style 

 which is bearded in the male is shorter in the female, and de- 

 stitute of pili, except a very few at the base of the fissure; this 

 fissure in the male opens but little ; in the female it is vei*y 

 much opened, having the margins bent back and the apices 

 recurved ; the apex is tlivided in the male, but the apices are 

 straight : the male capitulum is more oval, that of the female 

 more cylindrical inclining to conical. 



The part of the style which bears the stigma is waved in 

 the female, straight in the male ; in the female flat, bearing 

 the stigma on the edges generally of a deeper purple than tlie 

 lower part ; in the male compressed, cylindrical, of the same 

 shade of coloin* as the part below it. 



The male florets are more exserted beyond the scales of the 

 capitulum, and therefore longer in porj)ortion to it than the 

 females, which frequently project very little beyond the scales. 



It is not a little remarkable, that the separation of the sexes 

 sliould have been so long overlooked in this unfortunately most 

 abundant of weeds ; the great difference in the appearance of 

 the male and female flowers has not however passed altogether 

 unnoticed, for Roth in his Flora Gamanica*, having de- 

 scribed Scrratidci (our Cnicus) aj-vensis, says, " Variat primo 

 calyce minori ovato oblongo floribus duplo majoribus pallidio- 

 ribus, stigmatibus subbifidis erectis." This description, I 

 think, there can be no doubt refers to the male plant. 



It is I believe a connnon observation, that Cnicus arvensis 

 rarely produces seed: and this circumstance has been attri- 

 buted to its increasing so much by the root ; the se2:)aration of 

 the sexes however presents a much more satisfactory eJv.pliina- 

 tion : and I have mentioned before, that the plants of each sex 

 grow together in large patches without intermixture; hence 

 the chance of impregnation being effected is much diminished. 



A useful CEConomical application may perhaps be made of this 

 fact, particularly if the observation of Villars in his Histoire 

 (les Plantcs de JJaujihine be correct f: he says, that there is a 

 simj)le means of destroying this plant, which is by permitting 

 it to flower, after which it dies ; if, however, it be cut down 

 before flowering, it will increase in all directions. If the seeds 

 were perfect, it doe? not seem that much could be gained by 

 this plan : as however there is a great chance that they may 

 not be so, should it be true that the plant dies completely after 

 flowering, it may prove a safe and successful means of dimi- 

 nishing the quantity of this troublesome weed. 



I have examined several others of our native species of 



* Tom. ii. pars 2. p. 295. f Tom. iii, p. 23. 



Cur dims 



