A. E. Everest 367 



can no longer be accepted as favouring the suggestion that the antho- 

 cyans are oxidation products of the fiavones; its true interpretation has 

 yet to be sought. 



Chemical evidence has now established the facts : 



(1) That the anthocyans always occur asglucosides (anthocyanins). 



(2) That the same pigment may be capable of showing a blue, 

 purple or red colour, according as it exists as alkali salt, free pigment 

 or oxonium salt of some acid. All anthocyans do not, however, form 

 blue alkali salt.s. 



(3) That the anthocyans may be obtained from flavonols by reduc- 

 tion followed by spontaneous dehydration as shown above. 



(4) That glucosides of flavonols can pass, by reduction, toglucoside 

 anthocyans (anthocyanins) without intermediate hydrolysis. 



The points (3) and (4) doubtless apply also to flavones, but as no 

 natural anthocyans related to these have, as yet, been isolated, proof of 

 this is naturally unavailable. 



(5) All analytical evidence points to the molecular weights of the 

 anthocyanidins being of the order of those of the flavonols. 



The author does not propose to go deeply into the Mendelian 

 significance of the chemical results discussed above, but would suggest 

 that they appear to show that the factors R and B so frequently used 

 to represent the power to produce red and blue anthocyan pigment 

 respectively, are really complex factors representing power to produce 

 different conditions of acidity and alkalinity in the cell sap, together 

 with the power to produce anthocyan pigment independent of whether 

 it is in the red, purple or blue form. It ought also to be noted that 

 the factors R and B if looked upon thus must affect the production of 

 ivory and yellow, for it is well known that in many ivory flowers the 

 pigment of the flavone series is present, and it is only necessary to 

 make the cell sap alkaline in order to produce a fine yellow flower. 

 These are however matters that are better left for those researching 

 upon ISIendelian problems to deal with, but now that chemical investi- 

 gation has thus far cleared the ground, the problems involved in the 

 production of these pigments become somewhat more clear, and research 

 in this field of botanical work should be stimulated and helped thereby. 



Journ. of Gen. iv 24 



