30 Bulletin 313 



PoDOSPHAERA OXYACANTH^ (D. C.) de Bary (= Oidium crataegi 

 Grogn., page 116). — On leaves and other green parts of cherry, 

 Crataegus and other pomaceous and drupaceous fruits. Produces 

 meager but rather persistent mycelium. Perithecia scattered or 

 grouped, 64-90 /x; appendages arranged more or less equatorially, 

 variable in number (4-30) and length, dichotomously branching, 

 each branch more or less knob-shaped. Asci broadly obovate or 

 subglobose, 58-90 x 45-75 fj.; spores 8, rarely 6, 18-30 x 10-17 fi. 



109. Peritheciiim, 1/6. 110. Immature asci, 1/12. 111. Mature ascus, 1/12. 

 112. Ascospores, 1/12. 



