128 



COMPARATIVE MORPHOLOGY OF FUNGI 



Because of a peculiar weakening of sexual tendencies in the Ascomy- 

 cetes, plasmogamy early loses it obligatory character and becomes 

 facultative. This functional disturbance first affects morphologically 

 only the antheridia: these become superfluous and disappear, and instead 

 of amphimictic fertilization, appear all sorts of deuterogamous processes 

 which we shall later follow in detail under the individual orders. Gradu- 



Fig. 78. — Pyronema conflucns. Sexual organs. Antheridium, Anth, and ascogonium, arch, 

 with trichogyne, t. (X 1,750; after Claussen, 1912.) 



ally, however, this functional degeneration extends to the female organs; 

 they also degenerate and disappear. Eventually no organ is formed 

 and the plasmogamy becomes pseudogamous. 



Hand in hand with this degeneration, there also appears a shifting 

 of the significance of the sexual organs for the formation of fructifications. 

 Originally the laying down of the fructifications was begun by the 

 formation of sexual organs; hence the female organ was called archicarp. 

 In many higher forms, the fructifications begin their development inde- 



