43 CONNECTICUT EXPERIMENT STATION REPORT, IQI2. 



aurantiacus-miniatus on the edges where it is in contact with 

 glass or medium. 



On oat- juice agar the variety parasitica forms a somewhat 

 more evident aerial mycelium, but has fewer pustules and less 

 evident spore drops even than on the Lima bean- juice agar. It 

 usually has a deeper color, which varies from albus to luteus. 

 The species on oat-juice agar forms a very luxuriant growth, 

 even more so than on Lima, bean- juice agar, and though its 

 fruiting bodies are not so numerous, they are often evident 

 exposed pustules, only partially hidden by the spores mass, which 

 exudes with difficulty. The color assumes its maximum develop- 

 ment and is in strong contrast to that of the variety on the 

 same medium. It is usually more uniform and intense in color 

 than on the bean-juice agar, finally varying from luteus through 

 aurantiacus to miniatus and even badius when in contact with 

 the glass or medium. Part of the growth, especially on the 

 upper edge, however, often remains albus. 



The color of the spore masses of both forms varies in dif- 

 ferent cultures from sulphureus to nearly purpureus, depending 

 apparently on age, variation of the medium, bacterial contamina- 

 tion, or other unknown factors. Likewise, a culture when 

 renewed on the same medium sometimes acts somewhat differ- 

 ently for some unknown reason, as to luxuriance in mycelial 

 growth or spore development, or color characters. 



Tannic Acid in Cultures. Since tannin is found in such large 

 quantities in the wood of chestnut, and since this varies accord- 

 ing to the age of the tree, etc., it has been suggested previously 

 in this paper that this variation may have some bearing upon 

 the development of the chestnut blight. It was thought desir- 

 able, therefore, to study both the saprophytic Endothia gyrosa 

 and the variety parasitica in artificial cultures containing dif- 

 ferent percentages of tannic acid (M. C. W. brand, U. S. P.) 

 to determine how this affected their vigor, growth and spore 

 production. These cultures have all been made by Mr. Stoddard 

 under the writer's direction, and the data here given should be 

 credited to both investigators. We have used mainly for this 

 work two rather recent cultures of E. gyrosa on two species 

 of oak from Washington, D. C., and four cultures of E. gyrosa 

 var. parasitica on chestnut, two from Washington and two from 



