FUNGI. 



367 



noticed by the pomologist. This fungus is,described in Cooke's " Hand- 

 book of British Fungi " under the name of the Cladosporium dendriticum. 



In my notice of the Siberian Crab, I mentioned how seriously the 

 trees were injured in some years, as in the season of 1871. This is 

 due to another fungus (fig. 854), allied to the H. pyrorum, but both 

 Mr. Broome and Mr. Worthington Smith incHne to the opinion that 

 it is a species distinct from it. Mr. Smith writes to me that he 

 finds the spores of H. pyrorum measure '0004" x "OOOS", whilst those 

 of the Siberian Crab fungus measure -0004" x ■001". The Rev. Mr. 

 Berkeley thought the two were identical. There appears to me to 

 be some little uncertainty about these fungi, which, as they are very 

 important, deserve further attention. 



The Uredo filicmn (fig. 855) occasionally attacks our ferns. It 

 seems to prefer the Cystopteris fragilis when growing in our out- 

 door ferneries. It is of a yellow colour, lives on the fronds, and almost 

 gives them the appearance of golden ferns. 



Fig. 855. — Uredo filicum 

 (spore X 700 diam.). 



Fig. 854^7.— Tuber Kstivum 

 (spore X 250 diam.). 



Fig. S56. — Oldium friictigenum, 

 nat. size and magaified. 



Our plums and apples are attacked by a fungus called the Oidium 

 fructigenum (fig. 856), which rapidly causes the decay of the fruit. 

 Millions of spores are given off, and it is curious that every fruit is 

 not affected when exposed to the mischief; but as they are not, it 

 seems as though some antecedent condition of the fruit was requisite to 

 enable the fungus to grow. At the Fruit Committee of the Horticultural 

 Society, late-kept apples and pears when cut open are often permeated 

 with fungus, which renders the taste most disagreeable, although the 

 outward appearance is good. For this reason I have directed my fruit- 

 room to be well cleaned at the end of September, and then to have 



