254 SAGACITY AND MORALITY OF PLANTS. 



untold millions of years, for we find the fossil Lepi- 

 dodendra^ of the Carboniferous Period, riddled and 

 perforated by the minute interpenetrations of a 

 parasitical Fungus not distantly related to our too 

 well-known Potato-disease genus {Peronospord). 



Dr. M. C. Cooke, the distinguished fungologist 

 {Ftmgi, their Nature^ Influence, and Rises), says of 

 these ubiquities and geologically hereditary vege- 

 table robbers : "In the other section of the Coniorny- 

 cetes (Dust-funguses) the species are parasitic upon, 

 and destructive to, living plants, very seldom being 

 found on really dead substances, and even in such 

 rare cases undoubtedly developed during the life of 

 the tissues. Mostly the ultimate stage of these 

 parasites is exhibited in the ruptured cuticle, and 

 the dispersion of the dust-like spores ; but in Tilletia 

 caries, Thecaphora hyalina, and Puccinia incarcerata, 

 they remain enclosed within the fruit of the foster- 

 plant. The different genera exhibit in some in- 

 stances a liking for plants of certain orders on which 

 to develop themselves, Periderniiimi attacks the 

 Coniferce ; Gymno sporangium and Podisoma the 

 different species of Juniper ; Melampsora chiefly 

 the leaves of deciduous trees ; Roestelia attaches itself 

 to pomaceous (apple-fruited) trees ; whilst Graphiola 

 affects the PalmacecB ; and Endophyllnm the succul- 

 ent leaves of the house Leek. In ^cidinin a few 

 orders seem to be more liable to attack than others, 

 as the Compositce, Rammctdacece, Legnminosce, Labiates, 



