THE FUNGI WHICH CAUSE PLANT DISEASE 155 



richly branched apically. Of the seventy 

 or more species of the genus only one, 

 S. panizzei d Not., originally described 

 from fallen olive leaves in Italy, has been 

 charged with producing disease.*^ It has 

 within the last few years become very de- 

 structive in Italy. 



The Tiyblidiaces, with six genera and 

 some seventy species, are likewise chiefly 

 saprophytes with the possible exception of 

 the two genera Heterosphseria and Sclero- 

 derris. The former occurs on umbellifers 

 while the latter may contain the perfect 

 stage of certain currant and gooseberry 

 fungi (Mastomyces and Fuckelia) of Europe 

 as well as a European parasite of the wil- 

 low. 



Phacidiacese (p. 154) 



Fig. 110.— Stictis. D, 

 habit sketch, E, ascus 

 and paraphyses. Af- 

 ter Rehm 



Apothecia sunken, more or less erumpent, 

 disk-like or elongate, single or grouped, leathery or carbonous, 

 black, firm, opening by lobes or rifts. 



Key to Geneba of Phacidiaces 



Apothecia not inseparably united to the sub- 

 stratum I. Pseudophacidies. 



Spores elongate, hyaline, 1-cellcd 1. Pseudophacidium. 



Spores elongate, spindle-form or filiform, 

 multicellular. 

 Spores elongate to filiform, not muri- 

 form 

 Apothecia rounded, opening by a 

 rounded mouth 

 Spores elongate or spindle-form 



paraphyses, none 2. Dothiora, p. 156. 



Spores elongate-globoid, 2-celled; 



paraphyses present 3. Rhagadolobium. 



