ON THE WATSONIA 



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 when 

 hybridizing experiments are performed, that at 

 least give clues to the story of the evolution of 

 color. 



Analogies drawn from the study of the spec- 

 trum are also of aid, in connection with these prac- 

 tical observations, in developing theories of the 

 philosophy of flower-coloration, which, if they 

 cannot be said to be definitive, have at least a large 

 element of plausibility and are full of interest. 

 THE PHYSICAL BASIS OF COLOR 



It has been suggested that the earlier forms of 

 vegetation were probably red in color, where now 

 the leaf structures in general are universally 

 green; the basis for this belief being the observed 

 manner of reaction between plants of green foli- 

 age and those of red foliage when hybridized, the 

 fact that sea weeds are usually red, and the fur- 



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