26 
BULLETIN" 623, U. S. DEPARTMENT OF AGRICULTURE. 
in a Washington strain tree is shown in figures 7 and 8. Typical 
fruits of the limb sports borne by one tree grown from a single bud 
are shown in Plate XVI. This condition is conclusive evidence 
Fig. 
-Trunk and main limbs of the tree shown in figure 7. The branch marked with the band of cloth 
is the Unproductive strain sport. 
that the origin of the diverse strains of trees in Washington Navel 
orange orchards is due to the accidental propagation of limb sports, 
and it is an important reason for obtaining performance records for 
use in the selection of bud wood for propagation. 
