270 TIMBER AND SOME OF ITS DISEASES. [CH.XII 



matters is in reality only apparent indifference due to 

 want of information. 



Returning once more to the particular case in 

 question, it is obvious that our new knowledge points 

 to the desirability of keeping the seed-beds and 

 nurseries especially clean from groundsel and weeds 

 of that description : on the one hand, such weeds 

 are noxious in themselves, and on the other they 

 harbour the Coleosporium form of the fungus Perider- 

 mium under the best conditions for infection. It 

 may be added that it is known that the fungus can 

 go on being reproduced by the uredospores on the 

 groundsel-plants which live through the winter. 



