Chap. VI. ON HETEEOSTYLED PLANTS. 277 



— ^the greater or less power of fertilising and being 

 fertilised — may characterise the co-existing individuals 

 of the same species, in the same manner as they 

 characterise and have kept separate those groups of 

 indiyiduals, produced during the lapse of ages, which 

 we rank and denominate as distinct species. 



