in 



CLASSIFICATION OF FUNGI 



forest trees, causing deformities of the leaves or fruits, 

 or forming the unsightly witches' brooms with which 

 we are all familiar. 



Among the most important of tropical disease-pro- 

 ducing fungi, is Exoascus theobromae, Kitz. Bos. , and E. 

 bussei, von Faber, of the cacao (see page 183). However, 

 witches' brooms frequently develop from other causes. 



Order 3. ASPERGILLALES. This order contains the 

 common green moulds (Penicillium), which grow so 

 abundantly on decaying or preserved fruits and 



FIG. 27. Peach leaves affected with leaf curl, Exoascus deformans. 



vegetables and also on many other substances. The 

 fungus consists of a mass of mycelium which ramifies 

 throughout the food substance. The mycelia finally 

 come to the surface, branch and produce a chain of 

 conidial spores on the end of each branch. These spores 

 are produced in such great abundance as to give the 

 appearance of a thick coating of green powder. The 

 ascospores when formed are in capsules within the food 

 body. They are not common. These fungi are 

 responsible for much of the decay of fruits with which 

 we must contend. They also are associated with other 

 fungi in causing the decay of timbers. 



Order 4. PERISPORIALES. This order contains both 



