282 DIOECIOUS AND CHAP. Vli. 



species, which exist as males, females and hermaphro- 

 dites, the latter would have to be supplanted before 

 the species could become strictly dioecious ; but the 

 extinction of the hermaphrodite form would probably 

 not be difficult, as a complete separation of the sexes 

 appears often to be in some way beneficial. The males 

 and females would also have to be equalised in 

 number, or produced in some fitting proportion for the 

 effectual fertilisation of the females. 



There are, no doubt, many unknown laws which 

 govern the suppression of the male or female organs 

 in hermaphrodite plants, quite independently of any 

 tendency in them to become monoecious, dioecious, or 

 polygamous. We see this in those hermaphrodites 

 which from the rudiments still present manifestly 

 once possessed more stamens or pistils than they 

 now do, even twice as many, as a whole verticil has 

 often been suppressed. Robert Brown remarks* that 

 "the order of reduction or abortion of the stamina 

 in any natural family may with some confidence be 

 predicted," by observing in other members of the 

 family, in which their number is complete, the order 

 of the dehiscence of the anthers ; for the lesser per- 

 manence of an organ is generally connected with its 

 lesser perfection, and he judges of perfection by 

 priority of development. He also states that when- 

 ever there is a separation of the sexes in an her- 

 maphrodite plant, which bears flowers on a simple 

 spike, it is the females which expand first ; and this 

 he likewise attributes to the female sex being the 

 more perfect of the two, but why the female should 

 be thus valued he does not explain. 



* ' Trnns. Linn. Soc.' vol. xii. p. 98. Or ' Miscellaneous Works.' 

 ii. pp. 278-81. 



