726 The Trees of Great Britain and Ireland 



The swellings which affect the trunk or branches are due to the irritation of 

 the fungus mycelium, which is perennial and stimulates the wood and bark to 

 abnormal growth. These swellings become fissured and are entered by the 

 spores of other fungi, which rot the wood ; and the tree, if the stem is affected, 

 is often broken off at the weakened spot by storms or falls of snow. The 

 witches' brooms begin as young shoots, bearing small yellowish leaves, on the 

 under surface of which two rows of acidia are developed in August. These 

 shed their spores at the end of that month and the leaves soon afterwards die and 

 fall off. The affected shoots keep on growing, and develop into peculiar growths, 

 set upright generally on the branches, and consisting of numerous twigs anastomosed 

 together. The fungus passes one stage of its life on various species of Stellaria, 

 Cerastium, and their allies, and Fischer 1 recommends the extirpation of these plants 

 from nurseries in which the silver fir is raised. 



The silver fir is very liable in its native forests to be attacked by the mistletoe. 

 Modified roots, the so-called sinkers of the parasite, have been found in the wood 

 enclosed in forty annual rings and as much as 4 inches long, showing that mistletoe 

 may live on the tree for forty years. When the mistletoe dies the rootlets and 

 sinkers survive for a time, but finally moulder and fall to pieces. The affected parts 

 of the wood show numerous perforations, and exactly resemble the wood of a 

 target that has been penetrated by shot or small bullets. 2 



The bark of the silver fir remains alive on the surface to an advanced age ; and, 

 on this account, when branches, stems, or roots of adjoining trees get into contact, 

 they often become grafted together. This is the explanation of the curious 

 phenomenon of the vitality of the stumps of certain trees in forests. After the 

 stem is cut down, these stumps continue to increase in size and produce a callosity, 

 which eventually covers the stump in the form of a hemispherical cap. Such a 

 stump procures its nourishment from an adjoining tree, with which its roots have 

 become grafted. 3 



Cultivation 



The silver fir 4 was introduced into England about the beginning of the seventeenth 

 century ; but the exact date is uncertain. The earliest trees recorded are two 

 mentioned by Evelyn, 5 which were planted in 1603 by Serjeant Newdigate in 

 Harefield Park in Middlesex. These had attained about 80 feet high in 1679, but 

 from inquiries made by the late Dr. Masters, there is no doubt that they have long 

 since been cut down. 



Though in its own country the silver fir is a tree of the mountains, yet it 

 attains its greatest perfection in the south and west of England, Scotland, and 



1 Abstract of Fischer's paper m/ovrn. Hoy. Hart. Soc. xxvii. 272 (1902). 



* See Kerner, Nat. Hist. Plants, Eng. trans, i. 210, fig. 48 (1898). We have never seen or heard of mistletoe on the 

 silver fir in this country. 3 s ee Mathieu, Flore Forestiire, 529 (1897). 



4 Staves were found, in 1900, lining the ancient wells in the Roman city of Silchester, Hants; and the wood was 

 identified by Marshall Ward with A. pectinata. The casks, from which the staves had been taken, were probably imported 

 from the region of the Pyrenees, and had either contained wine or Samian ware. Cf. Clement Reid, in Archaeologia, Ivii. 

 253. 256 (I9 ] )- 6 Sylva, 106 (1679). 



