Chap. VI. ON HETEEOSTYLED PLANTS. 273 



animals which properly have their sexes separated; 

 for the two sexes are combined in a monstrous her- 

 maphrodite in a somewhat similar manner as the 

 two sexual forms are combined in the same flower of 

 an equal-styled variety of a heterostyled species. 



Final remarks. — The existence of plants which have 

 been rendered heterostyled is a highly remarkable 

 phenomenon, as the two or three forms of the same 

 undoubted species differ not only in important points 

 of structure, but in the nature of their reproductive 

 powers. As far as structure is concerned, the two 

 sexes of many animals and of some plants differ to an 

 extreme degree ; and in both kingdoms the ' same 

 species may consist of males, females, and hermaphro- 

 dites. Certain hermaphrodite cirripedes are aided in 

 their reproduction by a whole cluster of what I have 

 called complemental males, which differ wonderfully 

 froni the ordinary hermaphrodite form. With ants 

 we have males and females, and two or three castes of 

 sterile females or workers. With Termites there are, 

 as Fritz Miiller has shown, both winged and wingless 

 males and females, besides the workers. But in none 

 of these cases is there any reason to believe that the 

 several males or several females of the same species 

 differ in their sexual powers, except in the atrophied 

 condition of the reproductive organs in the workers of 

 social insects. Many hermaphrodite animals must 

 unite for reproduction, but the necessity of such 

 union apparently depends solely on their structure. 

 On the other hand, with heterostyled dimorphic 

 species there are two females and two sets of males, 

 and with trimorphic species three females and three 

 sets of males, which differ essentially in their sexual 



