BUD VARIATION IN THE WASHINGTON NAVEL ORANGE. 17 
of the Washington strain every season during the period of observa- 
tion. From the standpoint of the study of the behavior of citrus- 
fruit variations, this strain is one of the most interesting of those 
under consideration. 
The trees of the Thomson strain are heavy and regular bearers, 
have an open and drooping habit of growth, dense foliage, and large 
dark-green leaves. As a rule, the trees of this strain are not as 
vigorous growers as those of the Washington strain under similar 
conditions. 
The fruits, illustrations of which are shown in Plate III, are similar 
in shape and size to those of the Washington strain. They differ 
from them mainly in having a very smooth rind of a bright reddish 
orange color. The rind of the Thomson fruits is thinner and the rag 
is more abundant and coarser than that of the fruits of the Wash- 
ington strain. The smooth texture, bright reddish color, and hand- 
some appearance of the fruits is of distinct value from the market 
standpoint. The juice usually is less acid than that of oranges of 
the Washington strain and is lacking somewhat in flavor. The 
undesirable characteristics of the rag and the inferior quality of the 
juice are detrimental to the reputation of the fruits of this strain. 
The fruits are seedless and the navels variable in size and arrange- 
ment, usually medium to small, occasionally rudimentary. 
Among the interesting fruit variations observed in the Thomson 
trees are those having the Thomson rind characteristics and the 
Washington rag and juice qualities, a Thomson-Washington strain; 
and the reverse of this condition, a Washington-Thomson strain. 
AUSTRALIAN STRAIN. 
The name Australian seems to have been used frequently on 
account of the resemblance of the trees of this strain to those grown 
in California from certain Australian importations. It has gradually 
been adopted by citrus growers to indicate the rank-growing, unpro- 
ductive Washington Navel trees which bear coarse, inferior fruits. 
As a matter of fact, the name is used frequently to include several 
distinctly inferior variations of the variety and it is here used in 
this collective sense. 1 
The trees, an illustration of which is shown in figure 5, are either 
regularly unproductive or produce crops at irregular intervals. The 
typical trees have a peculiar upright habit of growth and usually 
show more than ordinary vegetative vigor. Many trees of this strain 
produce a very large number of suckers, which until recently have 
been highly prized for bud wood for use*in propagation. The foliage 
normally is sparse and the leaves are comparatively small, narrow, 
i In Bulletin 1, Division of Pomology, U. S. Department of Agriculture, on p. 67, under the head of 
"Navel (Australian)," the following statement concerning the. origin of this strain occurs: "Originally 
from Bahia, Brazil, by way of Australia and California. Tree shy bearer." 
14575°— 18— Bull. 623 2 
