58 Forest Club Annual 



produced pycnidia and conidia. A five year old chestnut branch 

 bearing a canker caused by the fungus produced up to June 1, 

 under similar heat and moisture conditions, five crops of conidial 

 threads from the same pycnidia. The threads of spores were 

 washed off with distilled water between experiments and the 

 specimen subjected to a temperature of 115 C. for one minute. 



PATHOLOGY. 

 Susceptibility of Various Hosts to the Fungus. 



The susceptibility of various hosts to the disease is a question 

 upon which pathologists have disagreed. This cannot be definitely 

 decided until the taxonomic relation of the true bark disease and 

 of very similar and closely related fungi has been determined. So 

 far no proof is in evidence that the bark disease grows on any 

 other living tree than the chestnut. A fungus which if not the 

 true blight fungus is similar to it has been found and reported 

 on dead red, white, black and chestnut oak, maple, and sumach. 

 The relationship of these fungi will be held for later discussion. 



Bailey and Ames (2) report a peculiar phenomenon in the 

 reversion of the chestnut to its primitive boreal form in which 

 the leaves produced subsequent to severe attacks of the bark dis- 

 ease frequently resemble those of the oak. The wood formed 

 by the diseased cambium is very similar anatomically to that of 

 the oak. 



Possibility of Securing an Antitoxin. 



The mycelium sends a ramification of hypae into the cam- 

 bium and through into the wood elements; along its path the 

 tissue becomes brown and dies from the poisoning effect of a 

 toxin which is secreted by the mycelium. The cortical paren- 

 chyma is thought to be killed in the same manner. An attempt 

 was made to secure an antitoxin which would inhibit the growth 

 of the fungus. The feasibility of such a medicinal remedy would 

 lie in the treatment of individual ornamental trees. At the out- 

 set the effect of two alkalies, lithium carbonate and sodium car- 

 bonate, was tested on the mycelial growth of the fungus. Find- 

 ing that the presence of these salts stopped the growth of the 

 fungus in culture, the effect of solutions was tried on seed- 

 lings in water cultures. Sodium carbonate solutions proved 

 deadly to the seedlings. The different strength solutions of lith- 

 ium carbonate acted differently in that a 33 per cent solution en- 

 tered the seedlings more readily than .2, .25, or .5 per cent solu- 

 tions. The ascent of the solutions in the tree was detected by 

 the spectroscope. 



