THE AMERICAN BOTANIST. 79 



marvellotis defenses have been evolved incidentally' and 

 not called into existence by the necessities of the plants 



themselves- 



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* 



Even greater apparent objections to the mutation 

 theory arise in connection w^ith the processes of pollina- 

 tion. Aside from a desired explanation of how it happened 

 that when the first entomophilous flowers were ready to 

 be pollinated there were insects with fully developed 

 appetites for pollen and nectar ready to do the pollinat- 

 ing, we still need something to account for the astonishing 

 reciprocal forms of flowers and insects. Flowers are not 

 onh' adapted to be pollinated by certain insects, but the 

 insects themselves are coated with hairy growths in just 

 the positions necessary to receive and transport the pollen. 

 We can easily perceive the hindrance to cross-pollination 

 it would have been, had the beetles with smooth and burn- 

 ished armor, instead of the bees and moths, developed a 



taste for the gifts of the flower. 



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* 



There are some species, like the buttercup and the 

 dandelion, that are pollinated by a great variety of insects 

 and therefore have little bearing on the case, out there are 

 others that appear to be absolutely incapable of self pol- 

 lination and yet are pollinated by a single species of insect. 

 Should this insect not appear at the right time, the flower 

 will set no seed. The classic instance of a Madagascar 

 orchid with a twelve-inch spur may be cited. This is pol- 

 linated by an insect with a proboscis long enough to reach 

 the nectar at the bottom of the spur and we find it difficult 

 to imagine any process of mutation by which insect and 

 flower could be so perfectly fitted to each other in a single 

 move. We wish Professor DeVries would explain. There 

 seems to be in any extensive flora, one or more species of 

 plants whose very existence seems dependent upon that of 

 a single species of insect rising with its rise and dying with 

 its disappearance. On this supposition many are accus- 

 tomed to account for the rarity of several of our native 

 orchids. 



