LUTHER BURBANK 
suited for development of the citrus fruits. The 
initial investigations through which the hardy 
orange is developed must be made in a more. 
favorable locality. 
I frequently mentioned my belief that a hardy 
orange could be developed, however, and it is 
satisfactory to record that experiments along this 
line have more recently been undertaken under 
the patronage of the United States Government. 
The variety known as Citrus trifoliata, a wild 
form which had never been much cultivated, was 
known to be exceptionally hardy. This was hy- 
bridized with the sweet orange in the Government 
experiments just referred to, and the early results 
are thought to be very promising. 
“Among the seedlings observed,” says Profes- 
sor E. M. East, “several have proven valuable. 
They form a new class of citrus fruits and have 
been called Citranges. Three of these varieties 
have been named the Rusk, the Willits, and the 
Morton. The Rusk, which is a hybrid of orange 
crossed by ftrifoliata, is a small fruit with a bitter 
tang like the pomelo. It makes excellent marma- 
lade and preserves. The Willits, coming from a 
cross of orange upon trifoliata, is a rough, but thin- 
skinned fruit, resembling an orange in appearance 
but a lemon in flavor. It is used as a condiment 
or for citrangeade. The Morton, coming from the 
[276] 
