THE SELF-FERTILIZATION OF PLANTS. 399 



In this work, he shows that many of the species of 

 Orchids, are incapable of self-fertilization, and are com- 

 pelled to be fertilized by means of insect agency, to 

 which the structure of the flower, is very elaborately 

 adapted. His argument is, that as these plants are 

 mechanically incapable of self-fertilization, and as the 

 contrivances of the flowers so manifestly subserve in- 

 sect agency, it follows, that there must be something 

 radically injurious in the process of self-fertilization; 

 and that an advantage is derived from a cross, with a 

 distinct flower. The whole argument presses upon 

 the fact, that the flowers are incapable of self-fertiliza- 

 tion. The adaptation to insect agency exists in other 

 flowers, which are able to fertilize themselves; and, 

 with these, no presumption therefore arises, that there 

 is a necessity for the cross which insects effect. 



But, the whole significance of his facts, is taken 

 away, when it is observed, that the original form of 

 the flowers, and of the plants, has been modified, in a 

 number of ways ; that many characters, as he shows, 

 have been reduced to a rudimentary condition, and 

 that the incapacity for self-fertilization (which is a 

 mechanical, or structural incapacity, and not a physio- 

 logical incapacity) has arisen (as may be shown, by 

 analogy with the forms of other species of the 

 same genus), from the reproductive organs, of the 

 plants, having become partially rudimentary in struc- 

 ture. The whole structure, of the flowers (barring, 

 the slightest, possible modification), is consistent with 

 adaptation to self-fertilization, as well as to insect 

 agency. The only detail wanting, is but a little more 



