138 



PRACTICAL BOTANY. 



is a recognized alternation of generations, though in many 

 species the sexual forms have become suppressed through 

 degeneration. Besides the undoubted Ascomycetes there 

 are plants that are doubtfully placed here. Among the 

 more common plants of the class are the blights that 

 grow on the Lilac (Micro splicer a friesii), on Hops (Podo- 



sphcera castagnei), on 

 the Cherry and Apple 

 ( Podosphoera tridac- 

 tyla), on the Willow 

 ( Uncinula adunca), on 

 Peas (Erysiphe martii), 

 on Grasses (Erysiphe 

 graminis), on Butter- 

 cups (Erysiphe commu- 

 m'), on Celery (Oer- 

 cospora apii). Other 

 members of the class 

 are the common molds 

 the herbarium mold 

 (Eurotium), the blue 

 mold ( Penicillium ). 

 The Truffles are inter- 

 esting members of the 

 class. They are na- 

 tives of Europe, in some 

 parts of which they are 

 cultivated J:QE. the market ; they occur to some extent in 

 America. The spore fruits are produced in the ground. 

 They are very large, being sometimes six inches in diam- 

 eter. These are the edible parts, and they are highly 

 prized as an article 'of food. One of the doubtful orders 

 includes ordinary yeast (Saccharomyces cerevisice) and 

 other related yeasts. Here also belong certain Lichen- 

 forming Fungi. 



FIG. 77. A vertical section through an 

 apothecium of the Lichen, Anaptychia 

 ciliaris, showing the spores in various 

 stages of advancement in the asci, 1, 2, 3, 

 4 ; p, the paraphyses of the hymenium ; 

 y, the subhymenial layer ; m, the loose 

 fungal constituents. (Goebel.) 



