374 Chemistry of Meudelian Factors for Floicer-Colour 



Other anthocyanins are represented as methyl deri\atives of 

 delphinidin : 



OCl OH ^°C' OH OCl OH 



\ HO/VS 

 /OH 

 OH 



Myrtillidin chloride. Onidin chloride. 



He points out moreover that the anthocyanidins in the acid-free 

 form may be regarded as forming a series of reduced Havones : 



Luteolin, kampherol, and 



fisetin CsHjoOs — *- CisHijOj pelargonidiii. 

 Quercetin CisHjoO^ — »■ C,5Hi„0s cyanidin. 

 Myricetin CjsHjoOg — *- CisHinO, delphinidin. 



Bringing Willstatter's views to bear upon the Mendelian factors for 

 flower-colour, we necessarily come to the following interpretations. The 

 chromogens of the pigments are flavones and the factor for colour is 

 the power to bring about a simple reduction of the flavone accompanied 

 by a change from divalent to tetravalent oxygen and a pyrone to a 

 quinonoid structure. If the cell-i5ap is neutral the anthocyanin has the 

 structure of an inner oxonium salt and is purple. A reddening factor 

 must be interpreted as one which produces an acid cell-sap whereby 

 the anthocyanin is enabled to form a red acid oxonium salt. Similarly 

 a bluing factor is one which produces an alkaline cell-sap, blue antho- 

 cyanin being an alkaline salt of the purple neutral compound. 



With the exception of the view that the anthocj'anins are derived 

 from flavones which was first suggested in 1909', the author's results 

 are not in agreement with those of Willstatter. In the case of 

 Antirrhinuin investigated by the author in conjunction with Ba-ssett, 

 there is no doubt that the chromogen is the flavone, apigenin. On 

 Willstatter's hypothesis that the anthocyanins are reduced flavones, the 

 formula for Antirrhinum anthocyanin should be CijHioOj (apigenin 

 being C15H10O5), giving the percentage composition : 



C ... 70-86%, 

 H ... 3-94 7,, 

 O ... 2.5-20 7„ 



' Wheldale, M., "On the Nature of Anthocyanin." Proc. Phil. Soc, Cambridge, 

 1909, Vol. XV. p. 137. 



