7 '^HE object of this hook is two-fold. All the fungi 
described are parasitic on living plants, and 
include many that are amongst the most serious 
pests with which the cultivator of plants has to contend. 
One object of the hook is to enable those interested in 
this branch of mycology to determine accurately the 
cause of injury, the first step towards a remedy. 
Secondly, although many hooks dealing with fungi 
have appeared of late, yet the important Families 
dealt with in this book have been persistently ignored, 
and the study of fungi has been revolutionised since 
the latest account of-these families appeared in this 
country. 
