a 
; 
MILDEW ON ROSES. 81 
(References continued from page 80.) 
surface of the leaf; f, the mycelium of the fungus; g, a conidiophore 
having conidia or spores, X 300. 
O, the winter form of the fungus, a minute, blackish perithecium, immersed 
in felted mycelium on the leaves or shoots: A, perithecium; i, append- 
ages, X 100. 
° 
oto Yes, oe 
ie \ FL 
ap et 
D, the breaking up of the perithecium in the spring or early summer: J, the 
perithecium broken up in which the ascus has been kept during the 
winter ; #, ascus free and discharging spores, X 200. 
E, winter spore germinating: /, spore; m, germ tube, X 200. 
F', summer spore germinating: n, spore; 0, germ tube, X 300 
F 
