566 THE POPULAR SCIENCE MONTHLY 



the investigators in this field, Van Fleet, 21 of the United States Depart- 

 ment of Agriculture, crossed Asiatic and European forms with the 

 American chestnuts, the latter consisting of Castanea deniata, the forest 

 tree, and C. pumila, a shrubby species growing in the southern states. 

 The last species appears, by-the-way, to be somewhat resistant to the 

 blight. Van Fleet says : 



The results of these undertakings have been successful, in the main. The 

 appearance in 1907 among our plantings of the terribly destructive new bark 

 disease organism, Endothia parasitica, put a summary termination to the ex- 

 periments with C. amcricana (dcntata) and its derivatives, but selection work has 

 since continued with self and chance-pollinated individuals of the chinquapin 

 and Asiatic types. . . . The Asiatic chestnuts, and the chinquapin-Asiatic hy- 

 brids, are plainly highly resistant. Few have shown any appearance of infec- 

 tion and when noticeable the injury is quite local in character. Second genera- 

 tion seedlings of chinquapin-crenata crosses show no disease at all although al- 

 ways exposed to infection. 



The nuts produced by these chinquapin-Asiatic hybrids are of de- 

 cidi dly superior quality, so that, if they continue free from disease, they 

 will solve the problem from the standpoint of the chestnut orchardist. 

 It is doubtful, however, whether they will ever attain the size of forest 

 trees. But it is quite possible that an immune variety for timber pur- 

 poses may be produced by crossing a form like the Chinese chestnut, 

 C. mollissima, with our native forest tree. 



Work of this kind is extremely valuable and. although slow in yield- 

 ing results, may eventually prove to be the only means of continuing the 

 existence in our land of a greatly esteemed tree. 



21 Van Fleet, Walter, "Chestnut Breeding Experience," Jour, of Heredity, 

 5: 19-25, 1914. 



