Fig. 20. — Rosellinia radiciperda. _ i, Ascigerous stage of the fungus showing the 

 periihecia, natural size ; 2, perithecia enlarged ; 3, section of same, showing the 

 wall to consist of two layers ; 4, ascus containing spores, also paraphyses, X 300 ; 



[Description continued on p. 117, 



