FUNGI. 147 



The various modes of reproduction met with in the fungi 

 may be conveniently studied under two sections — asexual 

 and sexual — at the same time bearing in mind that the two 

 modes, sufficiently marked in extreme examples, pass 

 almost uninterruptedly into each other. It is equally im- 

 portant to remember that, taking the class as a whole, there 

 is a gradual sequence from the distinctly sexual to the 

 asexual mode of reproduction. 



(i) Asexual Mode. — In the Saccharomycetes or yeast-fungi, 

 an individual consists of a single spherical or elliptical cell, 

 and reproduction .takes place by what is termed sprouting. 

 A small papilla appears on the wall of a cell, which continues 

 to increase in size for some time, the connection with the 

 parent-cell becoming constricted to a thin neck, and is 

 eventually separated by a septum at this point, the daughter- 

 cell becoming free. When growing in a favourable liquid 

 the sprouting takes place rapidly, one cell often producing 

 two or three daughter-cells, each in turn going through the 

 same process, the result being a more or less branched 

 hypha, formed of bead-like cells joined by narrow necks ; 

 eventually the cells separate, and in turn form new chains. 



In a second and much larger group, including all those 

 fungi belonging to the pufif-ball (Lycoperdori) and toadstool 

 (Agarkus) types, the asexual reproductive bodies are called 

 basidiospores, and originate as follows. Certain large 

 terminal cells called basidia produce at the free apex two, 

 or more frequently four, very slender spine-like outgrowths 

 called sterigmata ; the apex of each sterigma becomes 

 swollen, the protoplasm passes from the basidium into the 

 swollen apices of the sterigmata, which are then cut off by a 

 septum and fall away as mature basidiospores. 



In a third type the spores are formed within a mother-cell 



