124 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. 



blossoms. The latter are produced at the tips of young shoots coming 

 out in the spring from terminal buds on twigs of the previous year's 

 growth. These consist of miniature nuts, or ovaries, each bearing at its 



FIG. 2. Mature walnuts, dropping from shucks. (Courtesy Kruckeberg Press.) 



extremity a two-branched, feathery stigma, which is designed to catch 

 the pollen coming in the air from the catkins. After pollination the 

 stigmas wither away and the pistillate flowers develop into nuts. In 



