THALLOPHYTA— FUNOI 



73 



Besides these sexual and asexual modes of reproduction, vege- 

 tative reproduction yevj commonly occurs. In forms such as 

 Bacteria and yeast it is much the most general method, and 

 consists only of ordinary cell-divisions, the daughter cells at 

 once separating from the one which gives rise to them. Some- 

 times in yeast this separation does not at once take place, with 

 the result that chains of cells are produced {fig. 827). 



Fig. 824. 



Fig. 825. 



Fig. 826. 



Fig. 824. Stylogonidia or stylospores of Eurotium, formed by repeated abstric- 



tion from the basal cell. After Doilel-Port. Fig. 825. Teleutospores of 



Paccinia gramiois bursting tbrongh epidermis of straw. After Dobel-Port. 



Fig. 826. Two gonidangia of Achlya. a. Closed. B. Ruptured, aud 



allowing the zoogouidia a to escape, b. Mother cells of the latter after 

 escape of e, the zoogouidia, from them. Fig. 827. Two yeast cells bud- 

 dine. 



In other cases a h^'pha divides by the formation of transverse 

 septa into a number of cells, each of which becomes rounded 

 off, and the chain breaks up into single cells which are capable 

 of immediate germination. They are often called oidium cells. 

 More complex forms are the bodies known as sclerotia, which are 

 composed of a mass of hyphae closely felted together and covered 

 by a pseudo-cortex. These separate from the mycelium which 



