242 LESSONS WITS PLANTS 



between the wings. In crowding itself in, the bee 

 pushes down upon the keel, and its body is struck 

 by the shaft of pistil and stamens (Fig. 202). 

 Pollen is left upon its abdomen, and the next 

 flower visited may receive some of it. 



278a. This is only one example of the almost innumerable ways 

 in which flowers are pollinated by insects. Some of the special 

 contrivances for effecting pollination are remarkably beautiful and 

 exact. We have found that the orchids are highly specialized. 

 Much of this specialization is a direct adaptation to cross-polli- 

 nation by insects ; and the pupil who desires to pursue the subject 

 of cross-pollination should begin with Darwin's epoch-making work, 

 "The Various Contrivances by which Orchids are Fertilized by In- 

 sects." He should also have Mueller's "Cross-fertilization of Flowers." 



2786. A special literature has sprung up respecting the cross- 

 fertilization of flowers. The subject is a favorite, because it often 

 shows such marvellous adaptations to particular ends. There is 

 great danger, however, that study of the subject by beginners will 

 lead the pupil to feel that perfect and complete adaptation is a 

 universal fact in nature, and will cause him to overlook the non- 

 adaptations and the misfits, of which there are many. It is usually 

 better for the beginner to obtain a somewhat general view of 

 plants before going far into such special subjects ; but the above 

 observations suggest to him a rich field which awaits still further 

 exploration. 



278c. We are apt to assume that all structures and attributes of 

 plants are for some distinct purpose or use, and we then set out 

 to discover what those uses are. The inevitable result is that 

 we find adaptations when there may be none. Every feature of a 

 plant needs to be investigated for itself, in the light of its his- 

 tory or evolution. Some features may be found to be in process 

 of adaptation, others in process of obliteration, and others are at 

 the present time perfected; and it is likely that some others may 

 be merely concomitants or correlatives of other characters, having 

 been carried along with them and having no special significance. 



