THE FUNGI WHICH CAUSE PLANT DISEASE 157 



celled or muriform, hyaline or slightly yellowish; paraphyses 

 wanting. 

 D. virgultorum Fr. grows on birch. 



Clithris Fries (p. 156) 



A small genus of about twenty species found 

 on wood and bark; mainly saprophjrtes. 



Ascoma sunken, then erumpent, elongate, 

 with lip-like margins, dark colored; asci clavate, 

 8-spored, often blunt pointed; spores linear or 

 spindle-shaped, multicellular; paraphyses fili- 

 form, coiled apically, hyaline. 



C. quercina (Pers.) . Rehm. is found on oak 

 branches and is perhaps identical with C. atireus 

 Mass. on willows. C. juniperus is found on liv- 

 ing juniper. 



Phacidium Fries (p.- 156) 



Over seventy species chiefly on leaves or ' 



herbaceous stems. Ascoma single, flattened, Fig. hi.— ciithris. 



, . 1 J . 1 II- 1 Ascus with spores 



soon becommg lenticular, breaking open by and paraphyses. 

 an irregular rift; asci clavate, 8-spored; spores terRehm. 

 oyate or spindle-shaped, hyaline, 1-celled; paraphyses thread-like, 

 hyaline. Conidial form probably in part =Phyllachora. 

 P. infestans Karst. is a parasite on pine leaves. 



Trochila Fries (p. 156) 



Perithecia sunken and closed, later erumpent, black, leathery; 

 asci clavate 8-spored; spores long, hyaline, 1-celled; paraphyses 

 filamentose forming an epithelium. Fig. 112. 



T. popularum Desm. is thought by Potebnia ^ and Ed- 

 gerton ^'' to be the ascigerous form of Marssonia castagnei 

 D. &M. 



T. craterium is the ascigerous form of Gloeosporium para- 

 doxum. See p. 541. 



