22 BULLETIN 623, TJ. S. DEPARTMENT OF AGRICULTURE. 
objectionable. Because the character of the development of the 
navel inside the fruit can not always be determined by outside 
inspection, and for other reasons, these fruits often are overlooked 
by graders in the packing house and may be included in the regular 
pack. This strain is a frequent variation in Washington and Thom- 
son trees. 
LONG STRAIN. 
The trees of the Long strain are similar in appearance to those of 
the Washington strain and have about the same characteristics of 
growth, foliage, and production. 
The fruits, illustrations of which are shown in Plate XI, are mainly 
distinguished from those of the Washington strain by their peculiar 
long and cylindrical shape, which makes them poorly adapted for 
packing in the present commercial package. The fruits usually are of 
small to medium size and in color, texture, and other characteristics 
of the rind are similar to the Washington strain. The rag is small 
in quantity and tender, and the juice is abundant and of good 
quality. The fruits are seedless, and the navels usually are small 
to medium in size. Fruits of this strain are found frequently as 
individual fruit or limb sports in Washington and Thomson trees. 
CORRUGATED STRAIN. 
The trees of the Corrugated strain resemble the Thomson closely 
in production, habit of growth, and foliage characteristics. 
The fruits are very different from those of the other Washington 
Navel orange strains, being prominently ridged or corrugated, as 
shown in Plate XII. They usually are globose in shape and of large 
size. The rind is of medium thickness and the color deep orange. 
The rag is tender and small in quantity, and the juice is abundant and 
of good quality. The fruits are seedless and the navels small to 
medium in size. Fruits of this strain occur as individual fruit or 
limb variations in trees of the Washington and Thomson strains. 
On account of the peculiar and prominent marking of the fruits, this 
strain is one of the most interesting and important of those resulting 
from the bud variations of the Washington Navel orange. Its rather 
frequent occurrence and the successful transmission of its charac- 
teristics in propagation experiments furnish strong arguments for 
care in bud selection in the propagation of the citrus varieties. 
UNPRODUCTIVE STRAIN. 
The trees of the Unproductive strain, an illustration of which is 
shown in figure 6, have a very low production, are finely branched, 
and have a spreading habit of growth with sparse foliage. The 
leaves usually are small, narrow, and sharply pointed. The trees 
