70 OUR FARM CEOPS. 



tissues, is frequently met with on strong crops when laid 

 and injured by the rain, especially if the soil and weather 

 at the time be of an ungenial character; in that state the 

 whole plant is a ready recipient of the germs of this 

 fungus. When examined carefully through the microscope, 

 the spores, instead of having the club-shape of the Puc- 

 ciniagraminis, are more irregular and branched, whence 

 the name of Kladosporium herbarum 1 has been given 

 to it. 



The common berberry tree has been charged with exert- 

 ing a pernicious influence on the wheat crop, and pro- 

 ducing a blight sEcidium Berberidis similar to that of 

 the regular mildew. The tree is, without doubt, liable 

 to the attacks of this peculiar fungus, but its structure is 

 so very different from that of the mildew fungus that their 

 identity is scarcely probable. It has been the subject 

 of investigation by many eminent men; by Jussieu at 

 Trianon; by Horneman at Copenhagen; by Knight in 

 England; and recently by the Agricultural Society of 

 Lille, the results of which, however, leave us in the same 

 state of uncertainty as before. 



A few general remarks may not be out of place here in 

 reference to the nature of the parasitic fungi, the princi- 

 pal of which have been so briefly sketched. 



All fungi grow upon some kind of organized matter ; 

 none of them derive their food directly, either from the 

 soil, air, or water, as other plants do. They aid Nature 

 greatly in setting up and carrying out the process of decay 

 and decomposition. Some may appear to grow on healthy 

 spots, but these no doubt originated on a spot where 

 disease had already effected some alteration in the tissues, 

 which alteration they soon caused to spread to other parts. 

 They, none of them are of any size many so minute as 

 to require the practised eye of the microscopist to detect 



s, a branch. 



