244 Minnesota Plant Diseases. 



not very abundant in Minnesota it seems doubtful that any con- 

 siderable damage results from it. The fungus fruiting bodies 

 should be removed and destroyed. (Fig. 82.) 



Club fungus rots (Species of Clavaria). There are many 

 species of club fungi which occur on woods of various kinds in 

 Minnesota. These fungi, however, seem to prefer those logs 

 already in advanced stages of decay, or they may be found on 

 the ground where wood debris is abundant. They less fre- 

 quently occur on solid logs or timbers. They are not, there- 

 fore, usually counted in with the dangerous timber rots of our 

 state. (Figs. 10, 81, 83.) 



The coral fungus rot (Hydnum coralloidcs Scop.). This fun- 

 gus is very abundant in the hard woods of our state. The fruit- 

 ing bodies occur on the under sides of fallen logs, in hollow 

 logs or less frequently on standing trees. They vary greatly in 

 size. The smallest are seldom smaller than a man's hand, while 

 the largest would fill an ordinary water pail. The fruiting body 

 is pure white or very slightly tinged with yellow and is very 

 much branched. From the branches arise small teeth about 

 one-half inch in length, which are found chiefly on the under 

 side of the branches and hang down. The whole mass is not 

 unlike a delicate cluster of coral growths. These fruiting 

 bodies are higly prized by mushroom eaters as choice delicacies. 

 The mycelium, of course, lives in the wood where it causes de- 

 cay of the wood tissues. The spore-bearing basidia line the 

 whole surface of the teeth and the spores are white. The fun- 

 gus is not important as a timber rot. 



Closely related to the coral fungus are two other toothed 

 fungi which are also found on wood under conditions similar to 

 those of the coral fungus. 



The bear's-head fungus differs chiefly in the possession of 

 larger teeth and coarser texture. 



The medusa-head fungus produces fruiting bodies more yel- 

 lowish in color and the teeth are very much longer, often attain- 

 ing a length of several inches. The teeth are usually densely 

 packed together and the whole fruiting body presents a more 

 nearly solid mass than either of the preceding forms. It is 

 found on forest logs and stumps and specimens have been re- 

 ported on building timbers in cellars. (Figs. 81, 84, 119.) 



