TYPICAL FORMS OF PLANT KINGDOM 105 



Blaringhem succeeded, in the case of maize, in adding carpels 

 to the male flowers in which the stamens remained intact, and 

 thus obtained hermaphrodite flowers. This is probably what 

 happens in the analogous transformations observed in the 

 unisexual flowers of a certain number of other plants. 1 



Thus we have made our first point :— 



The sex of flowers is clearly a function of their nutrition, and not 

 determined in advance — at least, in a certain number of cases. 

 The fundamental identity of the phenomena of reproduction in 

 animals and plants is a no less incontestable fact, and we are 

 consequently justified in appealing from what is obvious in the 

 one kingdom to its application to the other. There are, as we 

 shall see, groups of hermaphrodite animals, but while 

 hermaphroditism is the rule in the higher plants, it is the 

 exception in animals, which indicates that its appearance is of 

 later origin, and explains why its causes can be more easily 

 understood. 



The conditions under which hermaphroditism has been ob- 

 served in the Animal Kingdom agree in establishing the fact that 

 it, too, is connected with some disturbance in nutrition, which 

 leads to the disappearance of the males and the transformation 

 of the females into hermaphrodites. This hermaphroditism is 

 brought about in a particular way ; the cells destined to produce 

 germ-cells are formed early and make their first appearance 

 during the period of growth ; when they are competing with 

 the somatic cells in the process of multiplication they evolve in 

 the direction of masculinity ; when maturity is attained, how- 

 ever, they are enabled to appropriate all the nutritive 

 substances, and then evolution is towards the female sex. 

 There is no simultaneity in the development of the two kinds 

 of germ-cells, except, perhaps, for a short transitional period in 

 certain animals such as the Oyster, 2 which begins as a male and 

 then becomes a female. This process is called protandrous 

 hermaphroditism. The converse may take place, but it is 

 extremely rare. Among the Cirripedes and the Nematodes 

 we often find supernumerary and useless males, which persist as 

 though to serve as witnesses of the mechanism that produces 

 hermaphrodi tism . We are thus j ustified in thinking that the same 

 may hold true in the Vegetable Kingdom ; that under new 

 conditions of nutrition, as in the case of vegetation which had 



1 Trianosperma, Dioscorea, Clematis. 2 XII. 



