198 ANTHOCYANINS AND GENETICS 



left on the shrub, it may grow further, ramify and evolve into a larger 

 group of branches. All of them keep true to the old type." Another 

 case is that of the hybrid from Veronica longifolia and its variety alba ; 

 the blue hybrid occasionally produces white flowers. We may also 

 include the production of green-leaved branches by the purple-leaved 

 Beech, Hazel, etc. Other cases are mentioned by Bateson (591) : for 

 example, Azalea, of which there are white varieties streaked with red 

 giving rise to self-red sports. Also Pelargonium', here the variety 

 altum which is normally red may produce very occasionally one or two 

 magenta petals, and, conversely, there is a variety 'Don Juan' which 

 may bear trusses or branches of red flowers, though the normal colour 

 is magenta. Another case of exceptional interest is that in which an 

 individual of the purple- winged 'Purple Invincible' variety of Lathyrus 

 developed a flower of the variety 'Miss Hunt' which is lacking in the 

 blue factor (Bateson, 524). 



With regard to bud-variation there are several fundamental points 

 to be borne in mind, and these have been well expressed by Bateson 

 (524, 591) from whom the following quotations are taken. First: 

 " when a bud-sport occurs on a plant, the difference between the sport 

 and the plant which produced it may be exactly that which in the case 

 of a seminal variety is proved to depend on allelomorphism." This 

 is exemplified in the cases given above, i.e. in the presence or absence 

 of factors controlling pigment formation (Antirrhinum, Ribes, Veronica, 

 Fagus, etc.). Secondly, on consideration of these cases, we may arrive 

 at the conclusion that the segregation of the allelomorphs which control 

 the production of colour must have taken place at some somatic division, 

 and "we are thus obliged to admit that it is not solely the reduction- 

 divisions which have the power of effecting segregation." The third 

 point is that: "The distribution of colour in this case (bud- variation) 

 lies outside the scheme of symmetry of the plant." For "though the 

 parts included in the sports show all the geometrical peculiarities proper 

 to the sport-variety, yet the sporting-buds themselves are not related 

 to each other according to any geometrical plan," just as striping itself 

 in the Carnation or Antirrhinum is not under geometrical control. And 

 it is precisely the plants with this disorderly arrangement of striping 

 which so often give rise to bud-sports 1 



1 Bateson (591) notes a most interesting case of bud-variation in the Azalea Vervaeana. 

 The flowers have symmetrical markings of one shade of red, and red streaks of another 

 shade. When self-red sports arise they are of the shade of the red streaks, not of the 

 symmetrical markings. 



