CHAPTER XXVII. 

 FUNGI (Continued). 



THE SAC FUNGI, OR ASCUS FUNGI. 

 (Class Ascomycetes.) 



422. General characters. The mycelium is septate, and 

 grows either within the substratum or upon the surface. In the 

 latter case it often sends branches, called haustoria, into the cells 

 of the host, to obtain nutriment. Many of the species are poly- 



Fig. 220. 



A, a perfect fungus (Cordyceps militaris) parasitic on pupa of a moth. Head por- 

 tion of the fungus enlarged, showing fruit bodies (perithecia) containing asci and spores. 

 B, an imperfect stage showing conidiophores bearing white masses of conidia. 



morphic, i.e., different stages in the life history of the same species 

 appear under different forms. Some of these forms are asexual 

 stages and bear conidia (asexual spores) which serve to multiply 



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