ANTHOCYANINS AND GENETICS 169 



as the wild hairy species or de Vries' glabrous strains (see original 

 paper) were employed in the cross. 



Shull (520) first mentions the results of crosses between white- and 

 purple-flowered Lychnis dioica, the purple being dominant. 



Later, Shull (546) published further results, in which he states that 

 two varieties of coloured flowers can be detected in Lychnis, i.e. a 

 reddish- and a bluish-purple. The former is dominant to the latter, 

 this being the reverse of what is found in other plants. Two factors 

 are necessary for formation of the bluish-purple, and a third factor 

 modifies this to reddish-purple. 



In a still later paper Shull (588) again states that the type has reddish- 

 purple flowers, and that there is a bluish-purple variety recessive to 

 the type. The albino is without anthocyanin. No albinos mated 

 together produced colour. Two new German strains were introduced 

 Melandrium album and M. rubrum. A certain individual of M. album 

 x white dioica gave reddish-purple offspring. M. rubrum x M. album 

 gave a mixture of both purple- and white-flowered offspring in the 

 proportion of 4 : 23. 



Matthiola. Our knowledge as regards the inheritance of colour 

 in this genus is due to the work of Saunders (475, 487, 496, 500, 506, 

 562). 



It is not known what variety represents most nearly the original 

 type, but if it be assumed that each variety arises by loss of some 

 factor from the type, then the latter would be represented by a plant 

 with pale purple flowers. Loss of a diluting factor gives rise to deep 

 purple; loss of another factor from the deep purple gives a duller shade 

 of purple termed 'plum.' 



Loss of the blueing factor B -from each of the above varieties 

 gives rise to the corresponding blue-red series; rose, a dilute variety; 

 carmine and crimson, deep varieties; and 'copper,' a dull red variety 

 represented by plum in the bluer series. 



Loss of a further factor from the blue-red class reveals a true, less 

 blue, red class containing a dilute variety, 'flesh,' and a recessive 

 deeper variety, 'terra-cotta.' 



Early in the experiments with Matthiola it was ascertained that 

 two factors are necessary for the production of colour, and that certain 

 white varieties crossed together produce coloured offspring, purple in 

 the original experiment, since one at least of the original whites used 

 contained the blueing factor, B. 



The varieties may be represented in the following scheme. C and 



