1913] 



Babcock: New Forryi of Juglans 



13 



In undertaking cross-pollination experiments it was reasoned 

 that the failure of a large number of careful efforts to secure 

 such a hybrid would discredit this hypothesis, while the produc- 

 tion of one such hybrid artificially would tend to strengthen it. 

 During the first year 's work the only oak experimented with was 

 the coast live oak, Quercus agrifolia, but in succeeding years one 

 or more other species were included in the trials. The female 

 flowers used were all on J. calif ornica trees in 1908, but since that 

 year an effort has been made (yet without success) to secure 

 reciprocal crosses. 



Experiments in 1908, 1909, and 1910 



Two indigenous walnut trees were selected. They were 

 located, one at the rear and the other at the front of a large city 

 lot in the suburbs of Los Angeles. Through the courtesy of the 

 residents, they were protected from interference during the 

 critical stage of the work. They will be designated as Tree I 

 and Tree II. 



Manila paper bags were placed over the pistillate catkins 

 almost as soon as they appeared and before pollen was being shed 

 by the staminate catkins. Oak pollen was collected in homeo- 



SUMMARY FOR 1908 



Tree I 



Number of Kumber of 



pathic vials and applied with camel's-hair brushes. In 1908 no 

 pollen was being shed on Tree I, even at the time of pollination. 

 On Tree II pollen was being shed but care was used not to expose 



