261 FUNGI. 



slices of potato tubers, etc., have been employed. Fresh horse- 

 dung, placed under a bell glass and kept in a humid atmosphere, 

 will soon be covered with Mucor, and in like manner the growth 

 of common moulds upon decayed fruit may be watched ; but this 

 can hardly be termed cultivation unless the spores of some indi- 

 vidual species are sown. Different sohitions have been proposed 

 for the growth of such conditions as the cells which induce fer- 

 mentation, to which yeast plants belong. A fly attacked by 

 Empusa muscte, if immersed in water, will develop one of the 

 Saprolegnia. 



The Uredines and other epiphyllons Coniomycetes will readily 

 germinate by placing the leaf which bears them on damp sand, 

 or keeping them in a humid atmosphere. Messrs. Tulasne and 

 De Bary have, in their numerous memoirs, detailed the methods 

 adopted by them for different species, both for germination of 

 the pseudospor*es and for impregnating healthy foster plants. 

 The germination of the pseudospores of the species of Podi- 

 soma may easily be induced, and secondary fruits obtained. The 

 germination of the spores of Tilletia is more difficult to accom- 

 plish, but this may be achieved. Mr. Berkeley found no difficulty, 

 and had the stem impregnated as well as the germen. On the 

 other hand, the pseudospores of Cystopus, when sown in water 

 on a slip of glass, will soon produce the curious little zoospores 

 in the manner already described. 



The sporidia of the Discomycetes, and some of the SpJiferiacei, 

 germinate readily in a drop of water on a slip of glass, although 

 not proceeding further than the protrusion of germ-tubes. A 

 form of slide has been devised for growing purposes, in which 

 the large covering glass is held in position, and one end of the 

 slip being kept immersed in a vessel of water, capillary attrac- 

 tion keeps up the supply for an indefinite period, so that there is 

 no fear of a check from the evaporation of the fluid. Even when 

 saccharine solutions are employed this method may be adopted. 



The special cultivation of the Peronosporei occupied the atten- 

 tion of Professor De Bary for a long time, and his experiences 

 are detailed in his memoir on that group,* but which are too 

 * De Bary, "Ann. des Sci. Nat." 4th series, vol. xx. 



