ASCOMYCETES 



363 



Oospores and zygospores tide the plant over unfavorable con- 

 ditions and produce new plants when favorable conditions return. 

 In combatting the disease-producing Phycomycetes, the control 

 of zoospores, conidia, and oospores must be considered. 



FIG. 314. Conjugation in Bread Mold. a, b, c, and d are successive 

 stages in conjugation. At a the short hyphae have just come together, while 

 at d the zygospore is formed, e, zygospore developing a new hypha bearing 

 a sporangium. X about 130. 



Ascomycetes (Sac Fungi and Lichens) 



General Description. To the Ascomycetes belong the largest 

 number of Fungi, and most of them are parasites. Many of our 

 most troublesome diseases are caused by these Fungi. Some, 



