ANTHOCYANINS AND GENETICS 179 



tuberosum, colour is confined to the upper surface. In S. etuberosum, 

 pigment is developed on the lower, and is inhibited on the upper surface. 

 In S. verrucosum both surfaces are probably free from inhibitors. 



Trifolium. Inheritance of anthocyanin in flowers and seeds. Red 

 in flower-colour is dominant to both white and blue (Raj anus, 579). 



Veronica longifolia. Colour (anthocyanin) dominant to its absence 

 (de Vries, 498). 



Viola cornuta. Colour (anthocyanin) dominant to its absence 

 (de Vries, 498). 



Zea Mays. Correns (476) made the first investigations on this 

 species. As regards characters connected with anthocyanin he states 

 that two such characters behave in a Mendelian way, i.e. colour in the 

 pericarp (red or absence of red), and colour in the aleurone layer (blue 

 or white). The degree of dominance was found to vary. 



Lock (493, 504) has published further results. He states that blue, 

 black or purple pigments are confined to cells of the aleurone layer. 

 Red is confined to the pericarp. The pigment is situated in the cells, 

 and to some extent also in the cell walls of the pericarp. He points 

 out that in cross-bred cobs, blue will occur mixed since the character 

 is not maternal; the pericarp colour, on the other hand, appears in 

 either all or none of the grains, as it is a maternal character. The 

 work includes a large number of results in connection with the cross, 

 blue x white and the reciprocal. The results show that there is 

 irregularity in the dominance of blue. Red colour in the pericarp 

 is dominant to its absence, and forms a simple Mendelian case. 



East & Hayes (553) have published extensive results on Maize. 

 They show that Lock's irregular results were due to the fact that the 

 whites he employed in crossing were carrying different factors. They 

 themselves worked with a variety having red (anthocyanin) pigment 

 in the aleurone layer, and the formation of this pigment was found to 

 be due to two factors, C and R. A third factor, P, modifies the red to 

 purple. There is also a fourth factor, I, which inhibits the red and 

 purple colour. Red pigment in the pericarp, cobs and silks, is dominant 

 to its absence. It may be present in each of these parts separately 

 and independently of the others. No plant has been obtained which 

 has red glumes and yet shows no red colour in other parts of the plant. 

 One, however, has been found that is pure for red glumes, and shows 

 no red in other parts with the exception of the silks. 



122 



