DISEASES AND ACCIDENTS. 31 



iii which the plants are growing ; from the stagnation of water 

 at their roots, and from being planted in places under the influence 

 of the smoke of large towns. Another source of disease is an 

 excessive flow of sap from wounds or mutilation of the trees 

 during the growing season, for which they have no adequate 

 compensating or healing power, and which are aggravated by the 

 rapid formation and flow of the resinous secretions. 



The Rev. M. J. Berkeley states that one of the fungoid diseases which 

 proves so destructive to Larch,* "is generated on the roots of felled 

 trees that have been left in the ground, whence it spreads to the 

 roots of the living plants. The spores penetrate the tissues of the 

 tree in the form of white fibres or threads, which first impair and 

 finally destroy the vitality of the parts they infest. This disease 

 occurs in almost any kind of soil; it is found to be more especially 

 prevalent where the land does not admit of complete drainage, a 

 circumstance which appears to be supported by the fact that the Larch 

 in its native mountains flourish most where, though abundantly supplied 

 with moisture, the water never stagnates, f These fungi are known 

 by the - scientific names of Polyplwrus abietinus, P. destructor, and 

 P. versicolor. Scarcely any Coniferous tree is exempt from their 

 ravages ; Pinus, Cedrus, Cypress, &c, have been killed by them, the 

 evil invariably originating from the roots that have been left in the 

 ground, and which seem to have an especial power in generating them. \ 

 The fungoid parasite which attacks the stems and branches of Conifers 

 is called Peziza calycina, § it may be found on every branch that has 

 been left on the ground after thinning. The evil from this cause 

 commences where the bark has suffered from some unknown accident, 

 and the secreting surface whether of the bark or the wood beneath 

 it dies. || 



Disease arising from deleterious matters absorbed by the roots, 

 shows itself in the yellowish sickly appearance of the foliage followed 

 by the stunted growth of the leader and terminal branchlets. It 

 occurs in soils containing soluble matters taken up by the spongelets 

 of the roots, and which, being deposited in the vessels and tubes, 

 first obstruct and finally prevent the free circulation of the sap before 

 the season's growth is completed. It has been observed that Abies 

 Bowjlasii and A. nolilis will not live upon oolite soils, If it is also 

 well known that many other kinds do not thrive upon chalk and 

 limestone soils. The readiness with which foreign matter is taken 

 up by water, is familiar in the case of "hard" water, which contains 



* Gardeners' Chronicle, 1859, p. 1015. 

 f Idem, 1863, p. 244. t Idem, I 86 ?. P- 26 - § Idem > 1859 > P- 1015 - 



|i Idem, 1859, p. 1015. IT Idem, 1865, p. 291. 



