FUNGI 



157 



gelatinous, dark-brown, shell-shaped masses, resembling 

 ears; still others resemble fleshy branching corals (Fig. 151), 

 and hence are called coral Fungi. 



In general, mushrooms are harmless and often useful 

 saprophytes, but there are also destructive parasitic forms 





FIG. 150. Mushroom with spine-like 

 processes instead of gills. After 

 GIBSON. 



Fio. 151. The common edible coral 

 fungus. After GIBSON. 



that attack forest-trees. The mycelium usually spreads 

 between the bark and the wood, sending special absorbing 

 branches into the wood, often even into the heart wood, 

 causing decay and weakening of the stem. The spore- 

 bearing structures are sent to the surface, and appear as 

 toadstools, bracket Fungi, etc. Spores are produced in 

 great profusion and infect other trees, the new mycelium 

 using wounds to effect its entrance. Some mycelia spread 

 through the soil, inoculating trees through their roots; while 



