256 CRYPTOGAMIC PLANTS INJURIOUS TO FOREST TREES. 



dead vegetable matter, there it will fasten itself, and under 

 favourable atmospheric conditions will quickly spring into vigorous 

 action and consume the substance it lives upon until it is so 

 decomposed as to no longer afford any sustenance to fungoid 

 organisms. 



When vegetable matter arrives at such a stage of decomposition, 

 it in general furnishes a safe and valuable manure for the growth 

 of other plants, without any risk of producing fungi deleterious to 

 vegetation. 



Of the many different species of ferns, lichens, mosses, and 

 other cryptogamic plants which infest trees, we have no time left 

 to speak in detail, but as few or none of them are true parasitical 

 plants like fungi, there is less occasion to say much about them. 

 Where such growths abound upon forest trees, it is generally 

 caused by peculiarities of soil or atmosphere, such as cool, damp 

 soil, and a close, moist atmosphere, both conditions being highly 

 conducive to the growth of cryptogamic plants. In the case of 

 forest trees infested by them, drainage and judicious thinning, and 

 exposure to air and light, is generally found to be the best pre- 

 ventive. 



In conclusion, I would recommend a thorough preparation of 

 the ground before planting, and the removal of all dead or decay- 

 ing wood likely to produce fungus, with careful attention to 

 drainage, and timely and judicious pruning and thinning, as the 

 best general means of preventing the attacks of cryptogams on 

 forest trees. When the trees are once attacked, especially by 

 fungoid cryptogams, the best and safest plan is to root them out 

 and burn them at once, to prevent the disease spreading to 

 other healthy trees. 



