CRYPTOGAMIC PLANTS INJURIOUS TO FOREST TREES. 255 



that none of the spores are allowed to escape into the soil, from 

 which they will again attack succeeding crops. The attacks 

 of superficial mildew may in general be prevented by due atten- 

 tion to the wants of the plant, watering, manuring, etc., so as to 

 keep it in a healthy and vigorous state. When trees are attacked 

 by these parasites, an application of sublimed sulphur, if properly 

 and perseveringly applied, is in almost every case a certain 

 remedy, the sulphurous (not sulphuric) acid which always more 

 or less accompanies the use of flowers of sulphur, being fatal to 

 all those minute fungoid organisms of the nature of mildew. I 

 am aware that such remedies as these can only be applied to a 

 limited extent in our forests and plantations ; but they can 

 always be applied in the nursery, and ought to be rigorously put 

 into force amongst all young trees, so as to ensure a clean, 

 healthy, and vigorous stock of plants for the formation of future 

 plantations. 



Of the various genera of fungi which attack the heartwood of 

 living trees, causing heart-rot or " pumping/' the primary cause of 

 their attacks is generally ascribed to exhaustion or weakening of 

 the vital force of the tree, from the poverty or ungenial nature of 

 the soil, the severity of climate, or the neglect of timely thinning 

 and consequent overcrowding, all of which are injurious and 

 debilitating in their effects, and render plantations suffering from 

 them more liable to become the prey of fungoid diseases. The 

 only cure known for the attacks of heart-rot fungus, is to cut 

 down and clear away every infected tree, burning all diseased 

 parts so as to prevent as much as possible the spread of the fungus 

 spores. Careful and judicious selection of the trees suitable for 

 the locality, and which are known to suit certain soils and climate, 

 a due and proper preparation of the ground before planting, 

 efficient shelter and protection where such are necessary, and a 

 regular and systematic attention to the pruning, thinning, and 

 other operations necessary for the health of the trees, are the best 

 preventives of heart-rot. 



I might go on, if time permitted, to give you many more ex- 

 amples of the pernicious nature of fungi when growing upon trees 

 and vegetation in general, and which are either the cause or effect 

 of disease and decay, and all the varieties of " rot " to which trees 

 in a living state are liable, as well as the dry-rot which plays such 

 havoc amongst them when they are converted into timber. 

 Wherever fungoid life finds a suitable pabulum, in either live or 



