316 PLANT-BREEDING 



mediates are still lacking, showing that the unit-character 

 is either present or absent, but cannot be divided into lesser 

 constituents. 



Such splittings are even more striking, whenever they 

 are produced on the different branches and flowers of the 

 same individual plant. The instance of the willow-leaved 

 Veronica has been dealt with; its flowers are either of a dark 

 blue or completely white, the unit which produces the dye 

 being wholly absent or present, but not in intermediate 

 degrees. A parallel case is that of the hybrid between the 

 orange and the lemon, which may show the separation of 

 its units within the same fruits, some parts having the color 

 and the juice of the orange and others those of the lemon. 



Crosses between species are more difficult to understand. 

 According to the general rule, all the single marks of the 

 parents are mixed up in the offspring so as to form quite a 

 new type. But if we look more closely into special cases, it 

 is often possible to see that definite units of the parents are 

 recognizable in the hybrids, and that their development is 

 often the same, though in other cases checked by the new 

 combination. A notable instance of this rule is a hybrid 

 between the red and the golden currant (Ribes sanguineum 

 and R. aureum), which is commonly cultivated in gardens 

 under the name of Gordon's currant (R. Gordonianum). It 

 has the form and hairiness of the leaves of its red parent, but 

 in the flowers the red and golden colors are combined so as 

 to give an intermediate tinge. The combination, however, 

 is not at all perfect and easily shows on petals and calyx, its 

 two distinct component colors. So it is also in the hybrid 

 of the ordinary and the yellow foxgloves. I have pollinated 

 the first with the dust of the second and had a beautiful lot 

 of hybrids which flowered richly during a series of years. 

 The foliage and spikes were almost those of the yellow parent, 

 the flowers being intermediate in size, yellow, but with a red 



