200 



THE FUNGI WHICH CAUSE PLANT DISEASE 



Hypomyces Fries (p. 197) 



Stroma an effused cottony subicnlvun, often of considerable 

 extent; perithecia numerous, usually thickly scattered and im- 

 mersed in the subiculum, rarely superficial; asci cylindric, 8-spored; 



spores fusoid or fusiform, 

 usually apiculate, rarely 

 blunt, 2-celled, hyaline; 

 conidial phase variable. 



This genus of some forty 

 species contains but few 

 > saprophytes, the majority 

 being parasitic, chiefly on 

 the larger fimgi. The genus 

 is of economic interest only 

 as affecting mushrooms, 

 though one species, H. 

 hyaclnthi has been found 

 causing secondary infec- 

 tion in onions, following 



„ ^ , „ "^ . a bacterial trouble, and 



Fig. 141. — ^Hypomyces ochraceus. B, pen- i • t> ■ i 



thecia; C, asci and spores; D, spores; E, co- another; H. SOlani KeinRe 



nidia; f . chlamydospores. After Tulasne. ^^^^^^^ ^ ^^^^^ ^^^^^ 



on potatoes. Chlamydospores and conidiospores develop, be- 

 longing to various form genera as Verticillium, Mycogone, Fuhgo, 

 Diplocladium, DictyUum, Sepedonium, Blastotrichum. 



Alhed to this genus are probably Mycogone rosea and M. per- 

 niciosa, which are destructive enemies of mushroom culture. 



Melanospora Corda (p. 197) 



Perithecia superficial, without a stroma, globose-pyriform or 

 flask-shaped, with a long neck which is usually clothed at the 

 tip with a fringe of hairs, perithecia often hairy; asci broadly 

 clavate, 4 to 8-spored; spores 1-celled, brown to brownish-black. 



The genus contains some forty species, mostly common 

 saproph3^es. 



M. damnosa (Sacc.) Lin. is serious on wheat and rye.^^'' '** 



