52 VINE DISEASE. 



If the fungus of the Vine be an MrysipJte, there is no reason to be 

 surprised at its injurious effects ; for the genus is eminently parasitical*, 

 and it always causes such a disturbance in the vitality of the plants on 

 which it feeds, as to produce more or less serious mischief to them. 



Everybody knows the damage which is often done to the cultivated 

 Hop by ErympJie Humuli, DC, to the Sycamores by E. bicornis. Walk., 

 to Hawthorn by E. clandestina, Pr., and by E, Pisi, DC, to the later 

 crops of peas. The disease which is so ruinous to the Peach-tree, and 

 which cultivators call mildew (le Blanc), is apparently caused solely by 

 Eryuphe pannosa^ Fr., a species which is very prejudicial to rose-bushes, 

 and which produces abundantly the conidia^ pycnidia^ and the tltecige- 

 rous conceptacula . No one, as far as I am aware, has ever hesitated to 

 attribute the atrophy, the malformation of parts, and the sterility, all of 

 which succeed the attacks .. of _EV^5ij5^<?, to aught but those Fungi; why 

 should that species which infests the Vine be less injurious? and why 

 seek further for the damage which the stem so infested invariably 

 manifests? It is a most gratuitous supposition, that the Vine must be 

 diseased before this parasite attacks it ; and this improbable conjecture 

 must equally extend to the many other wild or cultivated plants on 

 which other species of ErysipJie prey ] as in like manner to those vege- 

 tables which afford a nidus to the various species of Uredo^ Mytimiay 

 Udilago, many kinds of leaf-inhabiting Sphce^nas, and a multitude of 

 other parasitical Fungi. Doubtless, it may be admitted, that these 

 pests do not attack indiscriminately every individual of the species 

 which they inhabit ; and that the health, and age, and locality, and 

 physiological condition of the plants have some influence on the develop-^ 

 ment of the Fungus ; but this general qualification, while applying to 

 many peculiarities in these little vegetable productions, ceases to be 

 of force, when their enormous diffusion assumes the character of a 

 universal scourge, and becomes a phenomenon, alike beyond our know- 

 ledge and control. 



racter; for there are several, as E, Martii, Lev., E, communis, Tr., E, lampocarpa. 

 Dub., etc., and which are often in the same predicament, whether it be o\ving to the 

 plants which sustain them, the spot where they grow, or other undetermined causes. 

 * In several of the species, the filaments of the mycelium are furnished with small 

 round appendages, probably organs of suction. They are especially visible in E. Martn, 

 Lev., and K communis. Lev. Both M. Gasparini and M. Mohl have seen them in 

 the Tine, where, indeed, they are very perceptible. 



