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 

 1 5-20 /x ; spores linear-clavate, continuous, 50-60 X 2-2 "5 // ; 

 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^ ; spores in a parallel fascicle, filiform, apex thickened, 

 guttulate, hyaline, 100-140 x 1 '5-2 /x ; 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 

 Fyrenomycetae, 



Rhytisma acerinum, Fries. — Stroma forming thin, black, 

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



