ANTHOCYANINS AND GENETICS 197 



Emerson further maintains that de Vries' results for striping in 

 Antirrhinum indicate that this case is of a similar nature to Zea. Also 







the results obtained by Correns (537) in striped-flowered plants of 

 Mirabilis; these results show that plants with self-coloured flowers 

 behave as if they had occurred in an F 2 from a cross of striped by self- 

 coloured plants. But flowers from self-coloured branches on striped 

 plants produce few, if any, more self-coloured plants than flowers on 

 branches with striped flowers. As an explanation of this anomaly 

 Emerson suggests that in the case of seed sports the factors for variega- 

 tion are affected, whereas in somatic variations there is no corresponding 

 change in the Mendelian factors. 



A curious phenomenon in connection with striping in Antirrhinum 

 is one noted by the author and previously mentioned (see p. 159). 

 If the factor for tingeing with anthocyanin be denoted by L, and the 

 factor for full colour by D, then LLDD(d) is magenta and LlDD(d) 

 pale magenta. If in the striped variety we represent D by S, then 

 LLSS is ivory striped with magenta, L1SS, ivory striped with pale 

 magenta, LLSs is tinged ivory striped with magenta and LISs tinged 

 ivory striped with pale magenta. No explanation of this interesting 

 result can be offered at present. 



In Primula sinensis (Gregory, 557) striping appears to belong to a 

 different category from that in Antirrhinum, Mirabilis, etc., for it 

 behaves as a simple recessive to a self-coloured form. 



Bearing in mind the facts just recorded one cannot fail to realise 

 that the common occurrence of reversion to self-colour among striped 

 varieties is but one expression of the much more widely distributed 

 phenomenon of bud-variation. Of the latter there are a number of 

 cases known, many of them involving pigmentation. Some are con- 

 cerned with the distribution of chlorophyll, and these it is not necessary 

 to consider here. Of those connected with anthocyanin there are 

 several recorded by de Vries (498, 565), for instance in Ribes sanguineum, 

 Veronica longifolia and others. Ribes sanguineum has red racemes of 

 flowers and a certain amount of anthocyanin in its twigs and petioles, 

 and there is a variety which has white flowers tinged slightly with red, 

 while the vegetative parts lack pigmentation. Of the variation de 

 Vries says: "Occasionally this white-flowered currant reverts back 

 to the original red type and the reversion takes place in the bud. One 

 or two buds on a shrub bearing perhaps a thousand bunches of white 

 flowers produces twigs and leaves in which the red pigment is noticeable 

 and the flowers of which become brightly colored. If such a twig is 



