268 SOME RECENT RESEARCHES IN PLANT PHYSIOLOGY 



the subject. A summary of this work up to a recent date 

 has been given by Stewart (1915), so it will only be briefly 

 discussed here, from the standpoint of the physiologist 

 rather than of the pure chemist. 



As was previously mentioned, Wheldale (1909, 1; 1910, 

 2; 1911) considers the anthocyanins to be derivatives of 

 flavones and xanthones, and has isolated in a pure con- 

 dition both red and magenta anthocyanin from varieties of 

 Antirrhinum majus containing the pale yellow hydroxy- 

 flavone apigenin, and the deeper yellow luteolin, both of 

 which are probably combined as glucosides in the living 

 cell. The structure of these bodies, originally isolated by 

 Perkin, is shown below : 



O 



\/\/ CH 

 HO CO 



Apigenin. 



For the red and magenta anthocyanins and the above 

 two flavones, Wheldale (1913, 2) found the following per- 

 centage compositions : 



TABLE LX1II. 



ANALYSES OF ANTHOCYANINS AND FLAVONES. 



