362 PLANT DISEASES 



flexuous tips, mixed with the mycelium ; asci globose or 

 broadly ovate, 55-68x42-54 ^; spores up to 8, broadly 

 elliptic, hyaline, 15-20X12-15 p., 



Sphaerotheca mors-uvae, Berk, and Curt, Grev., iv. 

 p. 158. Mycelium dense, thickish, margin white, centre 

 brownish; perithecia minute, closely gregarious, black, 

 globoso-depressed, rugose, left prominent by the collapsing 

 mycelium, spores 1 5 /A long. 



Erysiphe, Hedw. Perithecia superficial, spherical or 

 hemispherical, submembranaceous, yellow then blackish; 

 appendages simple or vaguely branched, never dichotomous, 

 intermixed with the mycelium, often undifferentiated or 

 absent; asci, many in a perithecium ; spores hyaline; 

 conidia Oidium erysiphoides. 



Erysiphe communis, Fries, Summa Veg. Scand., p. 406. 

 Mycelium effused, arachnoid, persistent, or evanescent, 

 on both surfaces of the leaf; haustoria lobed ; perithecia 

 minute, scattered, or gregarious ; appendages short ; asci 

 subglobose, 4-8-spored, 4-8 in a perithecium, no X 72- 

 80 /u,; spores elliptical, 40-42, 20-22 p.. 



Astemla, Sacc. Perithecia seated on blackish, radiating, 

 subsuperficial mycelium, lenticular or globoso-depressed, 

 almost mouthless, membranaceous ; asci generally octo- 

 sporous ; spores continuous, hyaline. 



Astemla beijerinckii, Sacc., SylL, ix. 376 = Ascospora 

 beijerinckii, Vuill., Journ. de Bot.> 1888, p. 255 figs. 

 Mycelium plentiful, crustaceous ; perithecia globoso- 

 depressed; mouth very minute or absent, 100-130 /* diam., 

 black, carbonaceous, erumpent ; asci numerous (up to 40), 

 obovate, then cylindrical, 110X20/1; spores elliptical, 

 ends obtuse, continuous, hyaline, 17X5-7 /*. 



