18 



said of the charred wood of Libocedrus decurrem^'^ recemtly described. 

 So little is known of the chemical nature of the wood fiber that it 

 would be hazardous to attempt any discussion as to the role of any of 

 the compounds found in decomposition processes. Charred wood, 

 such as above referred to, is composed of a very small quantity of 

 hadromal and a large part of some substance that is not cellulose, but 

 possibly a derivative of it. 



In view of the fact that for some wood the changes induced by 

 fungi have been found to be due to enzyms secreted by their mycelia, 

 it seems probable that the change in the wood of the cedar is brought 

 about by an enzym. This enzym is probably distinct from any yet 

 found, because of the very different products found as a result of its 

 action. Many attempts have been made to secure it, but so far these 

 have failed because of the very small quantity of mycelium which it 

 was possible to get. 



An aqueous extract of the charred wood when treated with an 

 excess of alcohol gives a gray flocculent precipitate, which is soluble 

 in water. Wood fibers have been inmiersed in such a solution, but 

 they did not, even after standing several months, show any change. 



As in the case of white rot, little is known of the life history of the 

 fungus causing red rot. The changes which it induces have been 

 studied in many trees, and were as follows: The first symptom noted 

 in the heartwood was a slight change from red to brown over a con- 

 siderable area. As the brown deepened, fissures began to appear and 

 soon became very numerous. The wood shrank until pockets, such as 

 above described, were formed. These pockets are most common near 

 the base of the trees, where they become very large. They occur one 

 above another, and often two unite. After a certain period no further 

 increase in the number of pockets takes place, and the cessation of 

 growth, as shown by this fact, is one of the problems which remains 

 for solution, as does also the question why all growth of the mycelium 

 should cease in the heartwood of a tree after it dies or is cut 

 down. It seems to be a fact that many dead cedar trees are found 

 which are partially decayed, and apparently have been in such a condi- 

 tion for many years. In southwestern Missouri, where the cedar 

 grows on the rocky hillsides, many trees die after they have reached a 

 certain age, apparently because of lack of food and water supply. 

 Many of these trees are full of brown pockets, especially near the base. 



THE MYCELIUM. 



The mycelium of this fungus is very scanty, being found in quan- 

 tity only here and there. The younger hyphje. are pale and have 

 numerous clamps. They extend horizontally through the tracheids 



lyon Sohrenk, H., A disease of Taxodium distichwn known as peckiness; also a 

 similar one of Libocedrus decurrens. 



