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CLASS BASIDIOMYCETEAE 



Fig. 122. Class Basidiomyceteae, Coprinus lagopus Fr. (A) Monocaryon mycelium 

 bearing heads of oidia in mucilaginous drops. (B) Detail of oidiophore. (C) Oidia 

 (a, c) of one sexual phase fusing with monocaryon hyphae (6, d) of the opposite 

 (compatible) sexual phase. (Courtesy, Brodie: Ann. Botany, 45(178) :3 15-344.) 



"gemmae" and thin-walled binucleate "oidia," both of which give rise to 

 dicaryon mycelium, and also uninucleate oidia. The latter begin as 

 binucleate, spindle-shaped cells which become divided by a septum into 

 two uninucleate cells which fall apart to form the oidia. These latter upon 

 germination give rise to monocaryon mycelium. The sticky droplets con- 

 taining the oidia attract insects. Brodie (1931) has demonstrated that 

 small flies carry these oidia from monocaryon mycelium to monocaryon 

 mycelium in Coprinus while Craigie (1927) demonstrated the same thing 

 for Rusts. (Fig. 122.) 



In many of the Basidiomycetae the fungus occurs in two sexual 

 phases. It was shown by Vandendries (1924) and by Brodie (1931) 

 that the oidia from one phase are able to fertilize the mycelium of the 

 opposite phase as Craigie (1931) proved for the Rusts. The germinating 

 oidium unites with a cell of the monocaryon mycelium and thus initiates 

 the dicaryon stage of growth. This dicaryon cell may grow out by elonga- 

 tion and division into a dicaryon hypha or the nucleus introduced into this 

 cell by the oidium divides and one of the daughter nuclei passes through 

 the wall into the next cell and so on until the whole hypha is " diploidized " 

 as demonstrated by Lehfeldt (1923) and by Buller (1930). The latter made 



