296 



SCIENCE 



[N. S. Vol. XXXVIII. No. 974 



apart. Twelve subcultures made from the 

 original flasks also behaved exactly like E. 

 parasitica. Fifteen pyenospore streak cul- 

 tures on potato agar from the Chinese ma- 

 terial and the same number from American 

 material vs^ere made July 10. The develop- 

 ment in all these cultures was the same, giving 

 the characteristic growth and colors of the 

 parasite as recently described by the writers.' 

 The only difference noted was that the dis- 

 tinctive orange color of the mycelium at the 

 base of the cornmeal agar slants began to 

 show one day earlier in some of the Chinese 

 than in the American cultures. Cultures of 

 the parasite of both Chinese and American 

 origin were also made on sterile chestnut 

 twigs and on upright tubes of cornmeal agar 

 and oatmeal in flasks. In all eases the or- 

 ganism behaved in exactly the same manner 

 and gave a typical growth of the chestnut- 

 blight fungus. 



July 7 fourteen inoculations of several 

 sprouts of Castanea dentata, eight to ten cen- 

 timeters in diameter, were made in the vicin- 

 ity of Washington with m,ycelium from one 

 of the original cultures from the Chinese 

 specimen. Within one week all inoculations 

 showed evidence of disease. At the end of 

 nine days the sunken areas of bark about the 

 points of inoculation extended in some cases 

 1 to 1.5 cm. Microscopic examination showed 

 well-marked typical mycelial " fans " in the 

 bark. At the end of two weeks all of the 

 14 inoculations were rapidly developing and 

 showed diseased areas of sunken bark often 

 extending 2 to 3 cm. from the line of inocula- 

 tion. Many pycnidia were present, but no 

 spore threads or horns had appeared. The 

 characteristic mycelial " fans " were conspicu- 

 ous in the bark. None of the five checks 

 showed any signs of disease. At the last ex- 

 amination of the inoculations made August 11 

 all were developing rapidly. The largest 

 canker was 6 cm. wide and 14 cm. long. 

 Pycnidia of Endothia parasitica with extrud- 

 ing spore masses were abundant. Pyenospores 

 from these cankers appear identical in shape 



' ' ' Cultural Characters of the Chestnut-Blight 

 Fungus and its near Relatives, " Circ. No. 131, 

 B. P. I., Dept. Agr., July 5, 1913. 



and general appearance with those from the 

 original Chinese specimen and also with those 

 from American specimens. The measure- 

 ments of the pyenospores are as follows: 



From an American specimen : 



Maximum length 6.15 microns. 



Minimum length 3.42 microns. 



Average length 4.69 microns. 



Maximum width 2.3 microns. 



Minimum width 1.84 microns. 



Average width 2.09 microns. 



From Meyer's Chinese specimen: 



Maximum length 5.84 microns. 



Minimum length 3.3 microns. 



Average length 4.75 microns. 



Maximum width 2.38 microns. 



Minimmn width 1.84 microns. 



Average width 2.05 microns. 



Specimens from inoculations with the Chinese 

 fungus : 



Maximum length 6.3 microns. 



Minimum length 3.46 microns. 



Average length 4.67 microns. 



Maximum width 2.3 microns. 



Minimum width 1.76 microns. 



Average width 2.04 microns. 



Meyer's first specimen showed no perithecia. 

 On July 23 more Chinese specimens were re- 

 ceived from the same locality. These in- 

 cluded a large typical canker on a chestnut 

 branch about 6 cm. in diameter which agreed 

 in every respect with cankers produced on 

 varieties of Japanese chestnuts in this 

 country. Other specimens in this collection 

 showed well-developed perithecia and asco- 

 spores. Measurements of 100 ascospores from 

 the Chinese specimen gave a 



Maximum length of 11.1 microns. 



Minimum length of 6.9 microns. 



Average length of 8.4 microns. 



Maximum width of 5.3 microns. 



Minimum width of 3.5 microns. 



Average width of 4.39 microns. 



The same number of measurements from a 

 typical American specimen gave a 



Maximum length of 10.8 microns. 



Minimum length of 6.9 microns. 



Average length of 8.49 microns. 



Maximum width of 5.1 microns. 



Minimum width of 3.6 microns. 



Average width of 4.32 microns. 



