74 OUTLINES OF BRITISH FUNGOLGGY. 



from INIildew. But though the varieties which are strietly 

 Amcricau do not suffer, European kinds imported into the 

 United States are frequently affected; 



The Potato IMurrain arises from a INIould of very different 

 affinities, whose spawn attacks the tissues of the plant in 

 every direction, being present in the tubers and stems, as well 

 as in the leaves. It has a peculiar property of causing speedy 

 decomposition of the tissues with Avhich it comes in contact, 

 and hence induces rapid — sometimes inconceivably rapid ! — 

 decay. 



The sulphur remedy is not applicable here, because the 

 spawn is never superficial, as in the Grape and Hop Mildew ; 

 nor at present do we know of anything which effectually 

 checks its progress, though numberless plans have been sug- 

 gested. Early planting, and destruction of the haulm as soon 

 as the Fungus makes its appearance, give the best prospect of 

 success. 



The putrescence of Apples and other fruit is often pro- 

 moted by a similar cause, as first pointed out by Dr. Ilassall, 

 who induced decay in perfectly healthy fruit by inoculation, 

 but never apparently without some external lesion. A multi- 

 tude of other Fungi, belonging to various genera, induce dis- 

 ease in leaves, as in the Mulberry, Vine and hundreds of 

 other plants ; but I cannot speak of these now, but must pass 

 on to those species with loose dustlike fruit, which prey upon 

 our cereals, and other objects of cultivation in the fields. The 

 diseases produced by these are known under the name of 

 Smut, Bunt, Mildew,* Rust, etc., and are often extremely in- 



* It is unfortunate tliat tlic word Mildew (Melil Thau, meal dew) should be 

 applied to any Fungi besides the white Leaf Moulds. Its application lo a par- 

 ticular disease of wheat is universally diffused, and cannot be checked, though 

 constantly inducing error. 



