LA W OF PROGRESSIVE COLOURATION. 



59 



among Dicotyledons, and may therefore best be con- 

 sidered in the succeeding chapter. 



This brief review of the chief famih'es of Engh'sh 

 cntomophilous flowers will probably have made clear 

 the general truth of the law of progressive coloura- 

 tion here laid down. There are many exceptions and 

 special peculiarities, some of which will be explained 



I'll; 22.— Flower of common flag (Irisfa-tidisshiUi) ; vi.,lft i)!iie. 



or accounted for in the sequel ; but on the whole we 



may consider the following facts fairly proved : 



(I.) Most of the very simplest flowers arc yellow. 

 (2.) Many of the simpler flowers in each family 



(except the highest) are apt to be yellow. 

 (3.; The more advanced members of very simple 

 families are usually white or pink. 



