DISEASES OF VEGETABLES. 285 



attractive and suitable seed-bed for the fungi ; and, 

 therefore, advise the farmer to dress his ground 

 moderately to save his crop. Were the diminutive or 

 stunted plants never assailed by the rust, then the 

 above opinion may have some weight, and the advice 

 some value ; but in a blighting year, every wheat 

 plant, from the smallest to the largest, suffers ; showing- 

 that it is an atmospheric influence that predisposes 

 the plants to suffer, and the fungus to luxuriate. The 

 propagines or seeds of the fungus are impalpable and 

 invisible ; and being carried by the w r ind from place 

 to place, settle on every object, but come to perfection 

 only on such plants as are in a suitable condition to 

 receive them. 



The same species of fungus* or one nearly allied 

 to it, is frequently seen on the common berberry, 

 coltsfoot, and some other plants. Hence old fashioned 

 farmers eradicate the berberry from their hedges. A 

 laugh has been raised at this practice, but there is 

 more propriety in it than superficial observers are 

 disposed to allow. As the ovse float in the air there 

 are no means of averting the attack. Early and thick 

 sowing on sound and well drained ground, is the only 

 practicable preventive. 



Smut. This is a disease peculiar to cereal plants. 



* It lias been lately ascertained by J. Rennie, Esq. professor of 

 natural history in King's College, London, that the parasite fungus 

 on wheat is a distinct species, and not the same as that which attacks 

 the berberry and some other plants. This is confirmed by recent 

 discoveries of other naturalists. 



