LUTHER BURBANK 



practical difference whether you take pollen from 

 flower A to fertilize flower B, or pollen from flower 

 B to fertilize flower A. 



This observation, which was first made by the 

 early hybridizers of plants more than a century 

 ago, — notably by Kolreuter and by Von Gaertner, — 

 is fully confirmed by my observations on many 

 hundreds of species. Nevertheless it occasionally 

 happens that the plant experimenter gains some 

 advantage by using one cross rather than the 

 other. In the present case it seemed that by using 

 the Lawton as the poUenizing flower, and growing 

 berries on the brownish white species, a race was 

 produced with a more pronounced tendency to 

 vary. 



Still the plants that grew from seed thus pro- 

 duced bore only black berries in the first genera- 

 tion, just as when the cross was made the other 

 way. It thus appeared that the prepotency of 

 the Lawton manifested itself with full force and 

 certainty whether it was used as the staminate or 

 as the pistillate flower. 



When the flowers of this first filial generation 

 were interbred, however, the seed thus produced 

 proved its mixed heritage by growing into some 

 very strange forms of vine. One of these was a 

 blackberry that bloomed and fruited all the year. 

 This individual bush, instead of dying down like 



[44] 



