A GENETICO-PHYSIOLOGICAE STUDY ON THE FORMATION ETC. 
61 
was tlie derivative of apigenin and rose doré and magenta from lnteolin. Two 
factors are necessary to convert the cliromogen (luteolin) to magenta but only 
one is essential to rose doré. Thus 
yyiiRRbb 
yyiiRRBB 
White 
YYIIrrbb 
Ivory (apigenin) 
YYiirrbb 
Yellow (luteolin) 
YyiiRrbb 
Orange 
YyiiRrBb 
Crimson 
YyiiRrbb 
Rose doré 
YyliRrBB 
Magenta 
in which / is a dominant ivory factor, inhibiting the formation of luteolin. Y 
is the factor for yellow which is due to apigenin, R and B are the factors 
which convert the cliromogen to antliocyanin. 
The case of Linaria maroccana, studied by Correns (1912) 1 was as 
follows : Red is dominant over white, and purple over red. At present liis 
interpretation of the above case is hardly to be maintained. He dwelt upon 
the fact that antliocyanin is red in acid and blue in alkali and tried to inter¬ 
pret the factor difference of purple and red by that of acidity in the cell sap. 
But such seems to be unlike the usual case. Haas (1916) 2 found that the 
cell sap containing blue antliocyanin is acid or neutral but rarely alkaline if 
acidity is determined by the hydrogen gas chain. 
W illstätter attempted to explain the variation in the colour of cyanidin 
from red to blue by the quinonoid structure of the molecule. The phelolic 
character of the benzene ring allows the formation of salt with alkali, the red 
is the acid salt (oxonium salt) the blue is the potassium or metallic salt 
(alkali phenolate) and the violet is the anhydride of the pigment. But his 
hypothesis hardly explains how the deep blue antliocyanin can exist in the 
cell sap of the plant which is acid in reaction and further that an addition 
of alkali destroys the blue antliocyanin rather than deepening the colour. 
A new explanation of the causes of variation in the colour of flowers has 
been put forward by K. Shibata, Y. Shibata, and I. Kashiwagi (1919) ! based 
1. Correns, C., Die Neue Vererbungsgesetze. 1912. 
2. Haas, A. R., The Acidity of Plant Cells as shown by Natural Indicators. Jour. Biol. 
Chem. 27 : 233, 1916. 
3. Shibata, K., Shibata, Y., and Kashiwagi, I., Loc. cit. 
