328 LUTHER BURBANK 



That is to say, it usually seems to make no 

 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 Gtertner 

 — is fully confirmed by my own observations on 

 many hundreds of species. Nevertheless, it occa- 

 sionally 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 pollenizing 

 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. 



