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, 6, 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, 



