138 



BOTANY. 



Synopsis. — 



Vegetative part of the plant : mycelium on the surface of 

 the host sends suckers (haustoria) into the cells of the 

 host. 

 Propagative stage of the plant: short erect threads which 

 Willow mildew. \ bear chains of spores (gonidia). 



Fruiting part of the plant (perfect stage). 

 Perithecium with hooked appendages. 

 Perithecium contains sacs (asci). 



The sacs contain the spores (ascospores). 

 Uaterial. — Dried and pressed leaves of willow with the white mildew, also 

 older stages showing the numerous black ' ' specks, ' ' the fruit bodies, of the 

 mildew. Other species of the mildew may be used if preferred. 

 Microscope, etc. , 



