50 ON WHITE RUST. 



of the spongy tissue of the underside of the leaf, in which the 

 endochrorae instead of forming grains of chloropliyll had heen 

 organised into minute hyaline cells, simulating the spores of the 

 fungus ; a similar case to which occurred much about the same 

 time in the processes into which the outer cells of the cuticle are 

 converted in the pi'oduction known under the name of Erineum 

 aureum. The Erineum had been produced on the surface of the 

 ovaries and in every cell, the endochrome was converted into 

 hyaline grains resembling perfectly the spores of a true fungus. 

 The bodies represented by Fee are probably of the same nature. 

 A case approaching to this occurred also in the clavate cells with 

 which Lecythea epitea is surrounded. The endochrome did not 

 indeed form distinct cells, but was broken up into separate 

 granules, as far as I could see, not invested with a membrane and 

 endowed with very active molecular motion. 



Before closing the present observations I must call attention to 

 a very curious appearance which has this autumn accompanied 

 Helminthosporium pyrorum in the gardens of the Earl of 

 Westmoreland at Apethorpe. In the midst of the dingy patches 

 of the fungus, white spots appeared, not only on the leaves, but 

 also on the fruit, sometimes a quarter of an inch or even more 

 across, resembling very closely at first sight the Oidium, but not 

 blistering the leaves. On examination however it was clear that 

 the white appearance was not due to any fungus, but merely to a 

 disease of the cuticle itself, consisting of a sort of desquamation 

 like that of Lepra, the scales however being quite microscopic. 

 I was not able to examine this at a sufficiently early period to 

 trace its connection with the fungus, or to study its phases pro- 

 perly ; a somewhat similar case has occurred on Elm leaves, com- 

 municated by Mr. Broome. The matter certainly deserves further 

 iiotice, as it seems more properly a cutaneous affection, than some 

 other affections which have been so denominated. I am not prepared 

 to say that any real injury was caused to my pear trees by the 

 parasite, for the Glout Morceau bore an excellent crop of fine 

 fruit, and the Mai'ie Louise failed merely from the blossoms being 

 injured by late fi'ost. The peculiarly damp season may have had 

 some share in the appearance of this new parasite, but we have 



so in the walnut leaf there was a question whether the bodies might not be 

 very minute eggs. Dr. Montague had, as it appears, no opportunity of 

 examining the production in a perfectly fresh state, and therefore it is pos- 

 sible that the sti'ucture of Lis plant may really be more near that of the 

 pear leaf fungus than was at first appai-ent. If I mistake not the pro- 

 duction occurs in England. tho\tgh it has not been recorded. 



