ACCIDENTS, DISEASES, PAEASITES. 



193 



Rcesleria hypog&a. Has the aspect of small white 

 l)eads, greyish in colour, 5 to 6 rams, in height (Fig. 164). 

 The mycelium, which is very delicate, lives inside the tissues 

 of the' plant (Fig. 167). The underground development 



Fig. 161. Mycelium of 

 Agaricus Melleus, var. 

 subterranea (after R. 

 Hartig). 



Fig. 162. -Aciaricv* 

 Melleus. 



Fig. 163. Bunch of same at foot 

 of a vine. 



of the organs of the plant affected by pourridit, and the 

 fact that the mycelium of this cryptogam develops inside 

 the tissues of the roots, prevents the plant from being- 



Fig. 164. Rcesleria Hypogcea 

 on vine root. 



Fig. 165. Fructification 

 of Roesleria. 



Fig.166 Section of same 

 (after E. Prillieux). 



cured. We can only practically modify the constitution of 

 the soil so as to prevent the start of this disease or stop 

 its propagation if it has started to develop. The first 



10890. N 



