PAEASITIC FUNGI AND MOULDS. 4i 



the same French name, Pourridi^, which is found 

 in the south of France, and has been studied by 

 Planchon and Millardet. These naturalists describe 

 it as formed by the rhizomorphous mycelium of 

 a large hymenomycetous fungus, Agaricus melleus. 

 Roesleria is very different. It is a small white fun- 

 gus, with a white or ash-coloured head, from eight 

 to ten millimetres in size, of which the mycelium 

 lives in the interior of the vine-roots, penetrating 

 and profoundly affecting all the tissues of the roots, 

 and producing in the autumn the fructification which 

 comes to the surface. 



It is generally developed in marly and argillaceous 

 soils, after a rainy season, and in the low-lying parts 

 of vineyards on the slope of a hill. It thrives in 

 the moisture which lies below the surface of the soil, 

 and it is therefore important to improve the con- 

 dition of those sub-soils which are impermeable. 



It is also necessary to separate the stocks, so as 

 to prevent their roots from interlacing, and to uproot 

 and burn diseased vines, since the fungus may subsist 

 for several years in dead and dried roots. If, which 

 is almost always the case, any fragments of roots 

 remain in the ground, they will reinfect the sound 

 stocks which have been substituted for them. 



BemMrks on Diseases of the Vine. — We may be 

 surprised that this valuable plant, which has been 

 so carefully cultivated in France, should be attacked 

 by such a number of parasites, both animal and 



