192 Mr. H. O. Stephens on the Origin 



post, several feet below the surface. But the spores were in- 

 troduced with the horse-dung ; true, but this is produced by- 

 stabled horses fed on hay, and the Ag. campestris does not 

 grow in mowing grass, nor in the hay-making season, and 

 the hay could scarcely contain such abundance of spores ; 

 besides, is it probable such minute and delicate bodies would 

 pass through the digestive process of the animals' intestines 

 entirely unaltered ? It may be answered, oats frequently do ; 

 but the two cases are not alike. There is every reason for 

 believing Fungi are produced from spores : the circumstance 

 of exotic species appearing in foreign mould, e. g. Aseroe 

 rubra, La Billardiere, in earth from New Holland, seems to 

 prove this ; but to conclude they are invariably so produced, 

 appears to me to be assuming much more than we really 

 know, and that in the face of circumstances which render 

 the reverse very probable. 



In support of the hypothesis of the invariable origin of 

 Fungi from spores, it is stated that wheat selected from spe- 

 cimens infected with Uredo caries, when sown, produces a 

 bunty crop. This is scarcely a satisfactory argument, for 

 such wheat may possess the tendency to this disease without 

 being actually impregnated with the spores, just as we know 

 the finest samples of wheat from hot climates produce mil- 

 dewy crops when sown in our more cold and changeable lati- 

 tude ; besides, the experiments of Sir J. Banks with wheat 

 sprung from sources infected with Puccinia graminis led to 

 an opposite conclusion. It may be advanced, that wheat 

 growing near Barberry bushes is rendered mildewy by infec- 

 tion from the parasitic Fungus frequently abounding on 

 those trees ; but the Barberry parasite is an JEcidium, whilst 

 the plagues of wheat are always Puccinice or Uredines. The 

 greatest difficulty is in the erumpent Fungi ; how could they 

 reach the situations in which they vegetate ? It may be said 

 precisely the same question arises in Zoology, and the argu- 

 ments which apply to Entophytes will apply to Entozoa ; this 

 is only advancing a counter-difficulty, and the solution of one 

 problem would probably explain the other. Entophytes must 

 have their origin in one of the following methods : their 

 spores must be introduced into the parent plant, and there, 

 finding a suitable nidus and circumstances favourable for their 

 growth, commence their proper vegetation ; or the structures 

 in which they grow must, under favourable conditions, have 

 the power or quality of originating them out of their own 

 organization. 



There are difficulties in the way of both these theories. 

 Of the first, the question arises, how are they introduced in- 

 to the parent plant ? There appears to be only two ways. 



