54 BULLETIN 380, U. S. DEPARTMENT OF AGRICULTURE. 



limits in Pennsylvania include the northern localities known for 

 E. fluens, while the southern limits of this zone coincide closely with 

 the southern limit of E. fluent. 



The Livingstons (47) have published maps based on temperature 

 summations and temperature efficiencies, as well as maps in which 

 isoclimatic lines of temperature are combined with precipitation 

 indices and evaporation indices for the mean frost-less season. 



While no very definite relations between these maps and the ranges 

 of Endothia can be traced it is noteworthy that the localities where 

 Endothia gyrosa is known to be abundant are all south of or near 

 the 600 line of temperature efficiency, and only one collection of 

 E. gyrosa has been made north of the 400 line. E. singularis, on the 

 other hand, has thus far been found only north of the 400 line. 



Zon's map (86) of vegetal regions of the United States is based on 

 periods of growth and rest. The regions where Endothia gyrosa 

 and E. fluens are abundant are all south of the line which marks the 

 northern limit of seven months' vegetation. In fact this coincides 

 very closely with the northern limit of E. fluens, and no specimen of 

 E. gyrosa showing ascospores has been found farther north. 



The relations pointed out above strongly suggest the possibility of 

 some causal connection between climatic conditions and the present 

 ranges of Endothia species, but just what factors may limit the 

 spread of the species is not yet determined. The temperature tests 

 recorded on pages 45 to 48 throw little light on this problem, for the 

 maximum and minimum temperatures are about the same in the vari- 

 ous species. Endothia fluens seems to be less resistant to the effects of 

 high temperature (40 C.), but it is difficult to see that this fact alone 

 has any direct bearing on the question of distribution. 



DISCOVERY OF ENDOTHIA PARASITICA IN CHINA. 



For eight years after its discovery in the New York Zoological 

 Park in the summer of 1904, Endothia parasitica was known only 

 from eastern North America, During this time two quite different 

 opinions as to the origin of the fungus were advanced. Some in- 

 vestigators maintained that E. parasitica was an indigenous fungus 

 (15) ; others that it had been imported from some foreign coun- 

 try, probably oriental (51, 52.) In the fall of 1912, however, pyc- 

 nospore material was sent from Agassiz, B. C., by H. F. Giissow, 

 Dominion Botanist of Canada. Cultures made from this material 

 were identical with E. parasitica, and a series of inoculations on 

 Castanea dentata produced typical cankers. Later, a large quantity 

 of material collected at Agassiz by Dr. James R. Weir was received, 

 which included a few ascospores. These proved to be typical 

 E. parasitica. 



