STtJDY OF PATHOLOGY. 1& 



only a short time can intervene before the death of the 

 tree. 



' For a time, indeed, the still living tree, though greatly 

 reduced in strength, may put forth some desperate endea- 

 vours again to vegetate, during which it may bring forth 

 some abnormal short dwarfed branches, growing in what 

 may be called a rosette-like form, which, it may easily be 

 imagined, take on a quite original and strange appearance ; 

 but even in this case, though the death of the tree may be 

 deferred for a short time, the lifetime of the tree is, and 

 always remains, more or less limited. 



'Of fungi doing but little injury, perhaps ultimately it 

 may be found to be doing neither good nor harm to the 

 trees affected by them, there are these Phoma pinastri, 

 Lev., or Der Kiefern-pustelscorf, P. erythrellum, Thuem., or 

 Der Rothliche pustelscorf, and Leptostroma pinastri, Desm., 

 or Der Kiefem-duennscheibling ; we consider that we may 

 pass over these without further notice here. But a few 

 words must be given in regard to another, the Cladosporium 

 fumayo, Lk., or Russtkau, although it also does but little 

 injury. By the Russthau, as is generally known, is under- 

 stood the appearance occasioned by numerous fungoid 

 threads, which give to living plants, from trees and shrubs 

 of every sort, down to the most minute herbs and grasses, 

 and even to mosses, a look as if they were covered with 

 soot. Many investigators consider the fungi in question 

 as Saprophytes ; others, among whom we take a place, see 

 in them parasites, as observation shows that the appear- 

 ance of them is not necessarily preceded by that of honey- 

 dew (which Fleischman holds to be a regular precursor), 

 but the Cladosporium fumago especially can vegetate with 

 extraordinary luxuriance without honey-dew. One may 

 therefore reasonably infer that the Russthau fungus is a 

 parasitic organism, which, if it do possess no haustorium, still 

 finds nourishment from the plant on which it has found a 

 home ; and which may therefore assuredly be reckoned 

 amongst the injurious species. It is especially the casq 



