M. Wheldale 115 



Hence we may regard the dominant ivory factor in Antirrhinum as 

 the power to inhibit the formation of hiteolin. 



The difference between the ivory and 3'ellow varieties can however 

 be expressed in a more fundamental way. When the flavones are fused 

 at a high temperature with caustic alkali, a splitting of the molecule 

 takes place into a phenol, usually phlorogiucin, and a hydroxybenzoic 

 acid. It is most probable that the flavones, conversely, are synthesised 

 in the plant from the same phenols and acids, or their derivatives. 

 Hence the particular flavone synthesised depends on the hydro.Kybenzoic 

 acid formed in the plant. In the ivory variety the constitution of the 

 living molecule is such that only a monohydroxy acid can be formed, 

 whereas in the yellow a dihydroxy acid is formed in addition. More 

 than this cannot at present be said and no particular benefit is gained 

 at present by postulating an enzyme connected with the process. 



From the white variety no flavone could be extracted, nor do the 

 flowers give the canary -yellow colour when subjected to ammonia 

 vapour. 



The Anthocijanin Figments of Antirrhinum and Contaurea. 



By crossing yellow and ivory varieties with whites carrying suitable 

 factors, the anthocj'anin-containing varieties can be produced in F^ : 



■ YYiirrbb (yellow) x yijURRhh (white) — ■*■ YyiiRrhh (orange) 

 „ X yyiiRRBB (white) — >■ YyiiRrBh (crimson) 



YYIIrrbb (ivory) x yyiiRRbb (white) — ^ YyliRrbb (rose dore) 

 „ X yyiiRRBB (white) — >■ YyliRrBb (magenta) 



Thus it is obvious that in each of the above cases the constituents 

 of anthocyanin are separated in the two parents but when they come 

 together again in F^, the pigment can be formed. 



The universal distribution of flavones, the similarity in properties 

 between flavones and anthocyanins, and their intimate connection in 

 the above crosses led to the suggestion (Wheldale, 27, 28, 30), that 

 anthocyanins may be derivatives from flavones and that the white 

 variety contains some factor which modifies the flavone with formation 

 of anthocyanin. 



In the plant, the anthocyanins are present as glucosides, in solution 

 in the cell-sap of the epidermis of the corolla. From water or alcohol 

 solutions, they are precipitated as green lead salts, by addition of leac 

 acetate. 



