DISEASES OF CONIFEROUS TREES. 183 



tree i8 feet high, the first indications of disease being the 

 drooping, sickly appearance of the branch tips. Similar in- 

 stances of the death of Sequoia gigantea and Araucaria 

 imbricata by the above fungus could be given. 



Several species of Peridennium attack and cause much 

 damage to Finns insignis, P. /lalepensis, P. Sirobus^ and P. 

 montana. The disease not only causes an inordinate secretion 

 of turpentine, but the cambium of the wood is destroyed, and 

 the branches frequently die off in consequence. Pruning and 

 burning the injured portions of the attacked trees is to be 

 recommended, 



Peridermium columnare has of late years been very de- 

 structive to the silver fir {Abies pectinatd), less so to the 

 Cephalonian fir {A. cephalonicd) in several parts of Ireland 

 and elsewhere. When attacked, both the branches and leaves 

 wear a peculiar and conspicuous rusty appearance. Too close 

 growth of the trees is the main cause of attack, and judicious 

 thinning has, in several instances, put a premature end to the 

 spread of the fungus. 



Cedrus Deodara I have known to be completely killed out 

 by the presence in great quantities of a species of Polyporus ; 

 and at Ampthill, in Bedfordshire, an unusually large Cedrus 

 Libani was badly infested throughout with a similar fungus, 

 and had to be felled in consequence. 



The twiggy growths known as " witches brooms " are caused 

 by the mycelium of ^cidium elatirtum. They are found on 

 Abies Nordnianniana^ A. peetinata, A. Pinsapo^ A. balsamea^ 

 Pseudotsuga Douglasii, and other conifers. Pruning off and 

 burning affected branches is to be recommended. 



When growing in too damp soil, I have known Cryptoineria 

 Japonica, Sequoia gigantea, and Cttpressus macrocarpa, to have 

 their roots badly injured by the mycelium of a species oi Hym- 

 enomyceta; whilst, again, when planted in unsuitable soils, Picea 

 morinda, Piniis excelsa, and our common larch, suffer severely 

 from both Agaricus melleus and Polyporus sulphureus. 



I have known a nursery brake, containing 60,000 one-year- 

 old larches, entirely denuded by the mycelium of a fungus 



