380 
blight had been introduced from the 
Orient. Undoubtedly it had come in 
on Japanese nursery stock during the 
90’s of the past century. Had it come 
earlier, the disease would have made 
its appearance long before 1904. Later, 
Meyer found blight on Japanese chest- 
nuts growing in Japan. Both the 
Japanese and Chinese trees are highly 
resistant to blight. 
The virulence of the fungus on the 
American chestnut is analogous to the 
effect of tuberculosis on the Indian. 
In each case an organism was sud- 
denly introduced to a species which 
had never had the opportunity to 
build up resistance. Consequently, 
in both the havoc was extensive. 
Fortunately, many Indians survived: 
unfortunately, not a single infected 
American chestnut showed even mild 
resistance. 
With the discovery of the blight 
and the built-up resistance to it by 
oriental chestnuts, the Department of 
Agriculture sent botanists to the Ori- 
ent to select chestnut seeds for plant- 
ing in this country. This was done, 
even though at the time it seemed 
that the oriental trees were in every 
way inferior, except in resistance, to 
Americanchestnuts. The oriental trees 
appeared to be slow-growing and low- 
branching. Furthermore, the oriental 
trees could not be grown under the 
various conditions in which the native 
chestnut thrived. They required a 
warmer climate and more care. 
For years there was hope that our 
native trees would develop a resistant 
strain. Microscopic studies of the cells 
of the chestnut revealed that the living 
tissue of the tree fought the fungus— 
unsuccessfully, sad to relate—by in- 
creasing the width and the strength 
of the cell walls. What really kept 
hope alive, however, was discovery 
that the fungus never entered the 
roots of the tree—or at least could not 
survive there. Whether because of the 
greater amount of tannin in the roots 
or for other reasons, has not been 
definitely determined. Anyway, the 
root crown would continue to live for 
ANNUAL REPORT SMITHSONIAN INSTITUTION, 1948 
a while, sending up young shoots 
which frequently persisted long enough 
to bear viable nuts. 
The hope was that eventually one of 
these nuts would indicate some change 
in heredity, a mutation which would 
bring resistance into the germ plasm 
of the long-suffering species of native 
chestnut. But despite numerous trials, 
none was ever found to be resistant, 
although many were planted and 
tested either by natural or artificial 
inoculation with blight spores. So, at 
last, it was realized that the American 
chestnut was doomed. 
Revelation that much of the blight- 
killed timber could be utilized—that 
chestnut wood infected with blight 
actually contained more tannin than 
healthy wood—did not, of course, 
soften this stunning blow to the Amer- 
ican people. 
There was nothing to do but find a 
substitute for the American chestnut— 
if one could be found. So with the 
object of combining the best charac- 
teristics of the American chestnut with 
those of the oriental chestnuts, scien- 
tists began to cross the two types. 
Fortunately, they had access to early 
research. Walter Van Fleet, known 
especially among gardeners for his 
rose crosses, had been breeding orien- 
tal trees with native chestnuts in New 
Jersey. Because of this experience, he 
was selected by the Department of 
Agriculture to head up _ chestnut- 
breeding work at Bell, Md., where 
several of his oriental crosses are still 
in existence. 
Luther Burbank was another well- 
known plant breeder who had been 
crossing oriental, European, and na- 
tive chestnuts back in the 90’s. A 
number of Burbank’s crosses have 
found their way to Hamden, Conn., 
where Arthur H. Graves of the Brook- 
lyn Botanic Garden has been crossing 
chestnuts since 1930. Graves has been 
aided in his investigations by the 
Division of Forest Pathology, but the 
main breeding work of this division 
of the Department of Agriculture is 
still carried on in Maryland. 
