132 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. 



rowed bark much resembling that of Juglans nigra. All of these trees 

 bear medium sized, almost perfectly smooth nuts, similar to those of 

 the northern California black walnut trees found growing about the 

 various towns mentioned above. It is evident at first sight that these 



FIG. 5. Old black walnut tree at Walnut Grove, Napa County. 



are very old and on the decline. They are gradually dying all over the 

 tops and large limbs are breaking off and falling to the ground. 



Around each of the other basins in the hillside is found a group of 

 similar trees, some with single trunks, others composed of several stems 



