168 ANTHOCYANINS AND GENETICS 



Any plant without C or R is white. Hence whites can carry any 

 of the other factors in any combination or arrangement, but never 

 C and R simultaneously. There is also a certain connection between 

 colour and the hooded form of the standard. In hooded varieties the 

 standard always approaches in colour to the wings, and has never the 

 bicolor appearance of the varieties with erect standard. 



M. G. and D. Thoday (547) have given an account of experiments 

 with certain varieties of Lathyrus, and the crosses form a very complex 

 series in F 2 . The chief point of interest is that they find a scarlet 

 anthocyanin, distinct from, and recessive to. the bluish-pink of the 

 ' Painted Lady ' variety. 



Linaria alpina. Saunders (586) made crosses between the type and 

 a variety. The type has purplish- blue flowers and the variety pink 

 flowers. Both pigments are anthocyanins. It was found that blue 

 is dominant to pink. 



Linum usitatissimum. Varieties of this species have been investi- 

 gated by Tammes (564). Among other species, four varieties of 

 L. usitatissimum were used, i.e. common flax, Egyptian flax (deep 

 blue flowers), and two other varieties, one with pale blue, the other 

 with white, flowers. Among other crosses are the following which are 

 fairly typical. 



From Egyptian flax x white-flowered variety of common flax, the 

 F! had paler flowers than Egyptian flax. In F 2 there were 8 pale 

 blue, 3 pure white and 3 like Egyptian flax. This was regarded 

 as an ordinary Mendelian ratio of 1 : 2 : 1. From the white-flowered 

 variety x pale blue-flowered variety of common flax, the F x was fairly 

 constant, and still paler than the blue parent. In F 2 , out of 39 plants, 

 11 were pure white; the remainder were a mixture of pale blues like 

 the parent and grandparent, but were difficult to separate. The 

 author however believes the ratio to be again 1:2:1. 



In a later paper (610) Tammes shows that in the second and following 

 generations from a cross between the Egyptian and the white-flowered 

 varieties of common flax there is a deficiency of white-flowering plants. 

 This is found to be due to two causes, i.e. first, a deficiency of seed 

 formed from the mating of gametes without the factor for forming 

 colour, and secondly, an inferior germinating power of the seed of the 

 white-flowered individuals. 



Lychnis dioica. Saunders (475) used this species in certain crosses. 

 L. dioica was crossed with a glabrous form of L. vespertina, and a 

 glabrous variety of L. dioica was crossed with L. vespertina, F x and 

 their offspring showed pink, the depth of colour varying according 



