14 BULLETIN" 624, U. S. DEPARTMENT OF AGRICULTURE. 
this plat there are typical trees of 8 of the 12 most important strains 
of the Valencia variety and 3 of the minor strains, as follows: 75 
Valencia strain trees; 8 Unproductive; 7 Corrugated; 3 Sporting; 3 
Coarse; 2 Rough; 2 Smooth; 2 Barren; 1 Long; 1 Yellow; and 1 Small 
Yellow. Examples of the other 4 important strains and several 
minor variations occur as bud and limb sports in many of the trees. 
Although this plat is not an example of extreme variation of strain 
in established orchards, it is interesting to note that only 71 per cent 
of the trees in it are of the Valencia strain. Groves have been ob- 
served which were found to contain as large a percentage, and in 
some extreme cases more than this proportion, of trees other than 
those of the Valencia strain. 
The accompanying performance records, descriptions, and illus- 
trations only partially present the characteristics of the various 
strains. The real differences of the trees and fruits must be seen 
and studied personally before they can be fully appreciated and their 
importance in commercial fruit growing understood. For this same 
reason, the selection of trees from which to secure bud wood for prop- 
agation should not be made on the basis of the performance records 
of the trees alone. It is most desirable that the final choice be made 
in the orchards with the performance records in hand by someone 
who through close study and observation of the trees themselves 
has gained an intimate knowledge of the interrelation of tree charac- 
teristics and crop production. 
PRESENTATION OF DATA. 
The complete 4-year performance records of the 105 trees on which 
comparable data have been secured are presented in Table I. This 
shows the production by weight and number of fruit of each grade 
and size for each year and the annual average production for the 4- 
year period. The basis of ranking the trees in this table is the average 
annual total crop of each tree, expressed in pounds and ounces, with- 
out regard to the grade, quality, or uniformity of the fruit. Hence, 
the position of any particular tree in this table is not necessarily a true 
index of what its relative position would be if the classification were 
made on the basis of the commercial value of its fruit. The impos- 
sibility of making an accurate classification of a large number of trees 
on the basis of the comparative quality of the fruits and the desira- 
bility of the individual trees is the reason for the adoption of the 
weight of the average annual crop as a basis in preparing this table. 
