128 NUT GROWING 



will then present peculiarities in sexuality and we 

 shall have to allow for cross pollination requirements 

 in setting out nut tree orchards. Many varieties of 

 nut trees, like varieties of cherry trees, are not self- 

 pollinators. 



In a book published in Berlin in 1793, Christian 

 Konrad Sprengel first called attention to the fact 

 that the maturing of the stamens of the flower and 

 the pistils of the flower commonly occurred at dif- 

 ferent times. He deduced the conclusion, which is 

 now accepted by many authorities as a right one, 

 that Nature did not wish to have flowers fertilized 

 by their own pollen. On the other hand, eucalyptus 

 trees from the newer continent of Australia do not 

 raise the protecting lid from the flower until secure 

 self-pollination has occurred. This may leave us in 

 some doubt as to whether Nature has changed her 

 mind in recent times in relation to cross pollination 

 of older trees or if her laws are still immutable and 

 man is a cheap lawyer. 



Nature to-day, apparently, favors the origin of 

 new organic forms and apparently wishes to have 

 crossing occur only between varieties of a species 

 and not between species. We observe in hybridizing 

 work that the pistillate flowers of a plant accept the 

 pollen from another plant of the same variety more 

 readily than they accept the pollen of another species, 

 and there is some question if they would accept the 

 pollen of another species at all unless the pistillate 

 flowers are forced by accident or man's intention to 



