FUNGI. 367 



and very frequently the Easter Beurre", causing the fruit to crack and 

 prematurely rot ; so that really it is a very important fungus to be 

 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. Broom and Mr. Worthington Smith incline to the opinion that 

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

 finds the spores of H. pyromm measure "0004" x '0008", whilst those 

 of the Siberian crab fungus measure -0004" x -oooi". The Rev. Mr. 

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

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

 important, deserve further attention. I particularly called the atten- 

 tion of the Scientific Committee of the Horticultural Society to the 

 destructive properties of the Siberian crab fungus. 



The Uredo filicum (fig. 855) cccasionally attacks our ferns. It 

 seems to prefer the Cystopteris fragiiis 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. 



Fin 8 = 5. Ure j o filVum 

 (spore x 700 el'.anv). 



FIG. 856 Oi'Jium fructigemim, 

 nat. size and magnified. 



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

 fructigcnum (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 



