OIDIUM OB POWDERY MILDEW OF THE VINE. 



321 



Fig. 5. Various forms of Uncinula spiralis. 

 I, II. Perithecia showing /, appendages, and a, asci. 



III. Summer form showing m, mycelium; t, hyphae; c, conidia; and h, haustoria. 

 IV. Group of asci removed from perithecium emitting s, ascospores. (Ill and 



IV, after Viala.) 



V. Summer form of Oidium as it appears on surface of leaf. 

 VI. Ditto showing effect of sulfur (d). (V and VI, after Mares.) 



