170 STUDY OF COMMON PLANTS. 



blue iii the more highly developed ones, taken in connec- 

 tion with the striking modifications of form by which the 

 latter have become more and more perfectly adapted to 

 the visits of insects, gives some support to the theory 

 called the Law of Progressive Coloration. 1 



SPECIAL STUDIES. 



I. Colors of flowers belonging to the Ranunculacese. 



II. Various degrees of adaptation to fertilization by the 

 agency of insects in this family. Is self-fertiliza- 

 tion possible in the majority of cases ? Is it impos- 

 sible in any species ? 



III. Fruits of the Ranunculacese. 



IV. Dissemination of seeds. Special arrangements in 



Clematis and other genera. 



1 Cf . Grant Allen, Colors of Flowers, pp. 17-60 ; Miiller, Fertiliza- 

 tion of Flowers, pp. 88, 89. 



