Fig. 21. — Rosellinia necatrix. ^i, portionjof the] root of an apple-tree 

 partly covered with white, Heecy mycelium ; 2, brown hyphae showing 

 pear-shaped swellings, X300; 3, portion of an apple-tree root withsclerotia 

 bearing clusters of conidiophores, X 6 ; 4, a single tuft of conidiophores, 

 X 70 ; 5, a branch of the last, bearing conidia, X 300 ; 6, stylospores 

 produced in pycnidia, X 300 (after Viala) ; 7, peritheciuni surrounded Ijy 

 conidiophores, X 6 (after Viala); 8, ascospores, X 350 (after Viala); 9, a 

 sycamore infected with the fungus. The portion above ground is repre- 

 sented some fourteen days anterior to the rest. The plant is enveloped in 

 the white woolly mycelium, a ; on the subterranean portion Rhizoctiniae, 

 consisting of dark mycelium, h, b, are to be seen. Numerous sclerotia, 

 c, c, project from the surface. — (After Hartig.) 



