FUNGUS GROWTH ON TREES 97 



ception, as, when once established, it produces, 

 in respirations, water in sufficient quantity to 

 render the infected timber either moist or 

 sodden. The decay in mining timber, especi- 

 ally in coal-pits, is due in a great measure to 

 dry rot, and in Westminster Hall the oak 

 beams were found to be in many instances 

 attacked by this fungus in conjunction with 

 one of the boring beetles. In the Yorkshire 

 and Midland coal-pits, treating the timber 

 with creosote, carbolineum, or other antiseptics 

 is regularly resorted to. 



The canker of hard-wooded trees is brought 

 about by one of the Nectria (N. ditissima), and 

 is very common in every part of the country, 

 affecting the oak, beech, ash, sycamore, and 

 fruit trees generally. Ash perhaps suffers 

 most, the timber turning black and being quite 

 unfitted for structural purposes. It is strictly 

 parasitical, growing on wounded portions of 

 the stem and branch, and spreads with great 

 rapidity, attacking trees of all ages. We have 

 known the trees in a plantation of ash to be 

 quite destroyed by this canker, which attacks 

 most freely those growing on wet, sour land ; 



