ASCOMYCETES 377 



p. 44. Perithecia forming a single line on the nerve on 

 the under side of the leaf; spermogonia a year earlier on 

 the upper surface; asci clavate, apex narrowed, 70-100 x 

 15-20 p ; spores linear-clavate, continuous, 50-60 x 2-2*5 A* > 

 paraphyses hooked at the tips. 



Lophodermium pinastri, Chev., Flor. Paris, i. 430. 

 Perithecia scattered, many usually surrounded by a black 

 line, epiphyllous, innately immersed, elongated, black, 

 glabrous, finally longitudinally split, disc livid; asci 

 cylindric-clavate, apex narrowed, 8-spored, 115-165x14- 

 17 /A ; spores in a parallel fascicle, filiform, apex thickened, 

 guttulate, hyaline, ioo-i4oX i'5-2 /A; paraphyses slender, 

 tips curved. 



Discomycetaceae. Excipulum fleshy, rarely subcarbon- 

 aceous, clear-coloured, rarely blackish, glabrous, downy, 

 or hairy, closed at first, then expanding and exposing the 

 disc at maturity, sessile or stipitate, sometimes springing 

 from a sclerotium ; asci 4-8-rarely-many-spored ; spores 

 hyaline, rarely coloured, continuous or septate ; paraphyses 

 present. 



Rhytisma, Fries. Ascophores crowded on a thin, 

 broadly effused, black, crustlike stroma ; elongated, often 

 more or less wavy, finally gaping and exposing the pale 

 disc ; asci clavate, 8-spored ; spores linear, hyaline, 

 continuous, arranged in a parallel fascicle in the ascus ; 

 paraphyses slender, often curved at the tip. 



Conidia are formed on the stroma before the ascospores 

 in some species. By some considered as belonging to the 

 Pyrenomycetae. 



Rhytisma acerinum, Fries. Stroma forming thin, black, 

 crustlike patches on living leaves, J-i in. broad; ascophores 



