xxiv LIST OF ILLUSTRATIONS. 



FIG. PAGE 



126. Peronospora ganglioniformis, Berk., oospores with 



spiral vessel of Lettuce Leaf, x 400 . . . 273 



POTATO DISEASE. Peronospora infestans, Mont. 



127. Section through a fragment of potato leaf, with the 



fungus of the Potato Disease, Peronospora infestans, 

 Mont, in situ, x 100 284 



128. Fragment of upper part of conidiophore of fungus 



of Potato Disease, with conidia and zoospores ger- 

 minating, x400 287 



129. Conidium and zoospore of the fungus of Potato 



Disease, x 1000 288 



130. The sexual organs, or oogonia and antheridia of 



Peronospora infestans, Mont., x 400 . . .297 



131. Oogonium and antheridium of Peronospora infestans, 



Mont., xlOOO 298 



132. Pijthium vexans, D.By., x 400 .... 304 



133. Section through a fragment of a decayed potato leaf, 



with ripe resting-spores of Peronospora infestans, 

 Mont, in situ, x 100 305 



134. Section through a fragment of diseased potato tuber, 



with oospores of Peronospora infestans, Mont. , in 

 situ, x 400 306 



135. Peronospora infestans, Mont., oospores in British 



Museum, x 400 307 



136. Peronospora infestans, Mont., oospores germinating, 



x400 308 



137. Artotrogus as illustrated by Professor De Bary in 1881 313 



138. Darwin's Potato, Solanum Maglia, Sch. (Frontispiece). 



PARASITIC FUNGI AS FOUND IN A FOSSIL STATE. 



139. Peronosporites antiquarius, W.Sm., x 400 . . 332 



140. Protomycites protogenes, W.Sm., x 400 . . . 333 



141. Multiplication by cell-division in Cryptogams . 334 



142. Foot of common house-fly, with various fungus 



spores engraved to same scale, x 100 . . . 337 



143. Green fly from potato, natural size, and wing dusted 



with conidia of the potato fungus, x 20 . . 338 



