THE WATSONIA 81 



lias not attained any such degree of stability. 

 And, in particular, the color of the flower is 

 an endowment that, as contrasted with the gen- 

 eral structure of the plant, must be thought of 

 as only a thing of yesterday. We are justified 

 in believing that even among the old tribes of 

 plants those whose primeval forbears have 

 left their remains in the geological strata the 

 flower is the one structure that has been most 

 subject to variation. And we may doubt 

 whether there is any flower whatever that has 

 not changed its color more or less within com- 

 paratively recent times, geologically speaking. 



Something has been said as to the probable 

 relations of the different primary colors in their 

 various associations in the floral envelope. We 

 have seen that flowers of the same species may 

 vary from deep red to delicate violet, and that 

 it is the commonest thing for a species that is 

 usually gaudily colored to have representatives 

 that are pure white. And it is possible, by a 

 careful survey of the field, to draw conclusions 

 as to the probable sequence of development 

 through which the variously colored flowers 

 have been evolved. 



In the first place, certain inferences may be 

 drawn from what is known as to the hereditary 

 responses of different flowers, in particular 



