160 ANTHOCYANINS AND GENETICS 



on a ground tinged with magenta, whereas, when they are homozygous 

 in S, the ground colour between the stripings is ivory. The four 

 zygotic types may be represented as follows: 



1. YYIILLTTSS Ivory striped with I magenta. 



2. YYIIL1TTSS Ivory striped with P magenta. 



I. YYIILLTTSs T. ivory striped with I magenta. 



A. YYIILlTTSs T. ivory striped with P magenta. 



In 1910 Baur (536) published a full account of his work on Antir- 

 rhinum ; his results are in complete agreement with those of the author. 

 A comparison of the two sets of results was published by the author 

 (548) in 1910, together with further observations on the crossing of 

 certain additional, true red, varieties, rose dore (on ivory) and bronze 

 (rose dore on yellow). Rose dore is shown to be recessive to blue- 

 red or magenta ; similarly bronze is recessive to crimson. Both rose 

 dore and bronze occur in the tinged, pale and intermediate states. 



The work, published in 1913 and 1914 by Bassett and the author 1 

 on the pigments of Antirrhinum, has shown yellow to be identical with 

 the known substance luteolin, and ivory with the known substance 

 apigenin. The pigment in rose dore was shown to be a red anthocyanin, 

 and the same pigment mixed with yellow gives the colour, bronze; 

 similarly magenta contains a magenta anthocyanin, and this mixed 

 with yellow gives crimson colour. 



All the varieties may now be expressed in terms of the following 

 factors : 



Y. A factor leading to the production of luteolin in the lips and 

 apigenin in the tube. 



T. A factor leading to the suppression of luteolin in the lips, 

 apigenin being formed instead. 



L. A factor leading to the production of a tingeing of red pigment 

 in the lips. 



T. A factor leading to the production of a tingeing of red pigment 

 in the tube. 



D. A factor leading to the production of more anthocyanin pigment, 

 i.e. a deepening, or full-colour, factor. 



B. A factor converting red into magenta anthocyanin. 



1 Wheldale, M., & Bassett, H. LI., 'The Flower Pigments of Antirrhinum majus. 

 II. The Pale Yellow or Ivory Pigment,' Biochem. Journ., Cambridge, 1913, vn, pp. 

 441-444. 'The Chemical Interpretation of some Mendelian Factors for Flower-colour,' 

 Proc. E. Soc., London, 1914, LXXXVII B, pp. 300-311. 



