Form and Color in Nature. 249 



hundred or some thousand plants, exuded a drop of sweet 

 sap about the imperfect blossom, and wandering ants, or 

 bees, or butterflies happened upon it, and found it good. 

 Having emptied one, the most natural thing in the world 

 was to try another. The pollen accidentally caught upon the 

 head or the wings was carried along, and cross-fertilization 

 was effected. Time will not permit us to follow all the 

 steps, necessarily hypothetical, though substantially evident. 

 It is sufficient to point out that the plants which were thus 

 aided would be likely to perpetuate their race and to devel- 

 op their peculiarities ; that the insects which were benefited 

 were likely to acquire the habit of visiting the flowers which 

 had proved valuable to them ; that those flowers, in turn, 

 which most quickly and certainly attracted the attention of 

 their useful guests would be those which would most profit 

 by their visits. Thus there does not seem to remain a 

 shadow of a doubt that by reciprocal action on the part of 

 the insects and the flowers the showy petals and their varied 

 colors were produced. At first the petals were inconspicu- 

 ous or absent. When they appeared they were separate. 

 As the development proceeded they began to coalesce, and 

 this tendency became greater and greater, until in some in- 

 stances the individual petals totally disappeared, or left mere 

 traces, as in the tubular flowers. At the same time regu- 

 larity of form gave place to irregularity in many instances, 

 and this coincided with insect changes. As the tube of the 

 flower lengthened, the proboscis of the insect lengthened 

 likewise, and certain flowers became the feeding places of 

 special insects, upon which they wholly depended for fertili- 

 zation. In some instances the most elaborate arrangements 

 have been evolved to prevent self-fertilization and to insure 

 fertilization by the special insects upon which the flower 

 relies. The number of flowers of which this is true is enor- 

 mous, and these among the most common, as well as among 

 the most rare. A special study was made by Darwin of the 

 orchids, the arrangements in which family are of the most 

 curious and elaborate description. 



You will readily see that it is impossible for me to enter 

 upon detailed descriptions of these cases, of which the books 

 are full, and which any of you can observe for himself. 

 And no description can be needed to show you the nature 

 of the process. Take, for instance, the matter of color in 

 the blossom. "We know that at this moment most flowers 

 tend to vary more or less in color or tint. Such .tendency 

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