MERISTIC PHENOMENA 55 



cause," the sap is "so far changed as to constitute a Fruit quite 

 otherwise qualify'd." 18 We can add nothing to his speculation, 

 and we believe still that by a differential distribution of "fer- 

 ments" the sports are produced. All the factors are together 

 present in the normal parts; some are left out in the sport. 

 In an analogous case however, that of a variegated Pelargonium 

 which has green and also albino shoots, Baur proved that the 

 shoots pure in colour are also pure in their posterity. There 

 can be no doubt that the sports of Carnations, Azaleas, Chrysan- 

 themums, etc., would behave in the same way. 



The well-known Azaleas Perle de Ledeburg, President 

 Kerchove, and Vervaeana are familiar illustrations. Perle de 

 Ledeburg is predominantly white, but it has red streaks in some 

 of its flowers. It not very rarely gives off a self-red sport. This 

 is evidently due to the development of a bud in a red-bearing 

 area of the stem. The red in this plant is not under "geometrical 

 control." Many plants have white flowers with no markings, 

 but if the red markings are geometrically ordered differentiations, 

 no self-coloured sports are formed. The case of Vervaeana is a 

 good illustration of this proposition. It has white flowers with 

 red markings arranged in an orderly manner on the lower parts 

 of the petals, especially on the dorsal petals. This is one of the 

 Azaleas most liable to have red sports, and at first sight it might 

 seem that the sport represented the red of the central marks. 

 Examination however of a good many flowers shows that irregular 

 red streaks like those of Perle de Ledeburg occur, about as com- 

 monly as in that variety. Vervaeana in fact is Perle de Ledeburg 

 with definite red markings added, and its red sports obviously are 

 those branches the germs of which came in a patch of the stem 

 bearing these red elements. That this is the true account is 

 rendered quite obvious by the fact that the red of the sport is a 

 colour somewhat different from that of the definite marks, and 

 that these marks are still present on the red ground of the sporting 

 flowers. 



It will be understood that these remarks apply to those cases 

 in which the production of sports is habitual or frequent, and 



18 R. Boyle, The Origins of Formes and Qualities, Oxford, 1666. 



