form, believed that it had hitherto escaped the notice of botanists, occurring in an inconspicuous way as a weak parasite or saprophyte, but that conditions unfavorable to the chestnut, such as extremely cold winters and severe droughts, continued coppicing, etc., had rendered the tree susceptible to attack. As to the suddenness of the outbreak, this was to be accounted for by the very unusual climatic conditions which prevailed about the time of its appearance. Moreover, serious troubles of the chestnut had been before noted in this country, but had never been really explained.
On the other hand, those who believed the fungus to be an introduced species pointed to its apparent spread from the region around New York City as a center, our greatest port of entry, to the suddenness of the attack, to the fact that the fungus had never been observed here before, and lastly, to the partial immunity of certain varieties of the Japanese chestnut, which were first raised extensively on Long Island, the implication here being that the fungus might be a Japanese species to which, in their native home, the Japanese chestnuts had in the course of a long period of time become partially immune.
The last point was significant, but not conclusive, since the fungus had never been found in Japan, nor was it possible at the time to locate it in any foreign country.
In the course of time investigations brought out the fact that the fungus was closely related to a species already known in Europe and America, and by some was considered a variety of this, while others regarded it as a distinct species. Without going into details, it is sufficient to note the main fact emerging from them, namely, that the fungus was a new form, at least one not before known in Europe or America.
For a long time efforts to locate the fungus in the orient were without avail, but recently Mr. Frank N. Meyer, of the United States Department of Agriculture, has sent to Washington specimens from a blighted chestnut in China, which have been found to contain the identical fungus which has caused the trouble here. Moreover, from the nature of the locality in which it was collected, the fungus appeared to be indigenous. It should also be noted that the Chinese trees gave the appearance of being much more resistant to the disease than the American.[1]
Unless, indeed, we construct a theory of independent origin of species identically the same, due to essentially similar conditions of environment, we are justified, then, in believing that this parasite was brought into this country, and, judging from the past, may continue its steady
- ↑ Shear, C. L., and Stevens, N. E., "The Chestnut Blight Parasite (Endothia parasitica) from China," Science, N. S., 38: 295–297, 1913.
Metcalf, Haven, "The Chestnut Bark Disease," Jour. of Heredity, 5: 8, 1914.
