Fig. 21. — Roselliiiia necatrix. i portion of the root of an apple-tree 

 partly covered with white, fleecy myceb'uin 2, brown hyphae showing 

 pear-shaped swelUngs, X300; 3, portionof an apple-tree root with sclerotia 

 bearing clusters of conidiopbores, X6; 4, a single tuft of conidiophores, 

 X70; 5, a branch of the last, bearing conidia, x 300 ; 6, stylospores 

 produced in pycnidia, X 300 (after Viala); 7, perithecium surrounded by 

 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, b, b, are to be seen. Numerous sclerotia, 

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



