148 ANTHOCYANINS AND GENETICS 



William) the type was doubtless of a magenta shade and there is varia- 

 tion to crimson and also to a true red, 'Scarlet.' Similarly Primula 

 sinensis (Chinese Primrose) had in all probability a magenta type 

 (Hill, 577) and varies to crimson and true red, 'Orange King.' In 

 Antirrhinum majus (Wheldale, 535, 548) the type is magenta and the 

 red variety, 'Rose Dore': the case of Antirrhinum (Snapdragon) is 

 further complicated by the existence of a yellow variety (see below). 

 Variation to redness also occurs in Cheiranthus (Wall-flower), Hyacinthus 

 and others, but these are dealt with later in connection with more 

 complex series. 



Another variation-series is that which includes a yellow variety. 

 Colour in the yellow variety may be due either to plastid or soluble 

 pigment, and the two series have very different characteristics. It 

 should be emphasised that the soluble-yellow series is essentially 

 different from the plastid-yellow series. In the latter, as we have 

 already pointed out, the yellow is really the albino as regards antho- 

 cyanin pigment, whereas a soluble yellow variety is formed, as a rule, 

 by the loss of a factor from an albino. In the case of the plastid- 

 yellow series, further complexities, in addition to the simple loss of 

 anthocyanin, are introduced by variation in the plastid colours, or by 

 total loss of these pigments. 



To deal first with the soluble-yellow series: Antirrhinum majus 

 forms a typical example. The type is magenta; loss of anthocyanin 

 gives an ivory-white variety. From the ivory a soluble-yellow variety 

 is derived; mixture of yellow with the magenta anthocyanin of the 

 type, i.e. simultaneous presence of both pigments, produces another 

 variety, crimson. A red variety, 'Rose Dore,' has arisen from the 

 magenta, and a mixture again of rose dore with yellow results in another 

 variety, bronze. Finally there is a white variety which contains neither 

 anthocyanin nor yellow pigment. Hence the series can be expressed: 

 magenta, crimson, rose dore, bronze, ivory 1 , yellow and white. Though 

 we have no exact knowledge of the colour relationships in Althaea 

 rosea (Hollyhock), Dahlia variabilis and Dianthus Caryophyllus (Carna- 

 tion), yet these species in the main exhibit a similar series to Antirrhinum, 

 for they produce magenta, crimson, yellow and ivory-white varieties; 

 D. Caryophyllus, however, is characterised by many other shades. It 



1 In the soluble-yellow series ivory or ivory-white is used for the albino, which is 

 without anthocyanin, in contrast to the true white which is without both anthocyanin 

 and soluble yellow pigment. At present the only two species in which both these 

 varieties are known are Antirrhinum majus and Phlox Drummondii. 



