CHAPTER XXXVIII 



MOLD OR HYPHOMYCETE GROUP 



THE term Hyphomycete, as usually interpreted, is one of con- 

 venience only, for within this group are included members of the 

 fourjgreat divisions of fungi generally recognized by botanists. The 

 members of the group are many times not closely related. They 

 all resemble each other in having a plant body or mycelium, which 

 consists of threads or hyphce made up, in the majority of forms, of 

 chains of cells. Reproduction is not generally by budding, 1 ^ 

 although this may sometimes occur. The hyphae themselves break 

 up into spores, or spores are borne at the tips of hyphae that have 

 been differentiated for the purpose. The hyphae may unite to 

 form a more or less solid mass, sometimes tissue-like in appearance. 

 This mass may remain viable when dried for a considerable time, 

 and may function in much the same manner as a resistant spore 

 in tiding the organism over unfavorable conditions. Such a 

 structure is called a sclerotium. The names given to these various 

 types of structures have already been discussed under the heading 

 of Morphology in Section I. f^ 



The Hyphomycetes, for the most part, belong to the division 

 of fungi termed Fungi imperfecti by the botanist. The name is 

 derived from the fact that these fungi are not known to produce 

 perfect or sexual spores. Hundreds of genera and thousands of 

 species have been described as belonging to this group. Many of 

 these are doubtless simply developmental stages of forms that 

 are known under other names. The lil<- history of some fungi 

 has been found to be so complex, and consists of so many stages, 

 that five or six names have been applied and the different stages 

 put in different groups of fungi, until it was found that all were 

 the same polymorphic species. Unfortunately, careful mor- 

 phological study has not been made of the pathogenic mcmlx r^ 

 of this group, and there is the greatest confusion in tho nonrien- 



