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BIOLOGY AND HUMAN LIFE 



2. Ascomycetes (fungi bearing spores in sacs). The useful 

 yeast has already been described (Fig. 178). The edible morel 

 (a very delicious "mushroom") and a few other usable fungi 



Fig. 177. Downy mildew on grapes 



This fungus represents a large group of parasites that annually cause serious damage 

 to many of our cultivated fruits and vegetables. (From Duggar's "Fungous Diseases 



of Plants") 



belong here. There are many mildews and other parasites upon 

 useful plants, as well as many that destroy dead organic matter, 

 often causing serious damage to cloth or leather goods that are 

 allowed to remain damp, and to railroad ties and cut lumber. 



