i 9 4 TEXT-BOOK OF FUNGI 



Then again, to be consistent, what is the status of the 

 enormous assemblage of typically conidial forms collec- 

 tively constituting the Basidiomycetes ? These are all ac- 

 cepted as species, which, if a conidial form cannot be so 

 termed, is again a mistake. 



It is important to bear in mind that in the sexual 

 generation the reproductive bodies are the result of a 

 sexual act, or, at all events, were once sexual in origin, even 

 if at the present day its sexual organs are effete ; in the 

 conidial generation the reproductive bodies are asexual in 

 origin. 



The sexual generation was dominant in the most primi- 

 tive groups of fungi, whereas the asexual or conidial phase 

 was intermittent. In the latest group of fungi the asexual 

 or conidial phase is universal, and the sexual generation 

 absent. This change was probably rendered possible by 

 the evolution of Dangeard's conjugation of nuclei at a 

 certain phase of development, which completely superseded 

 the original sexual method ; and which, whether technically 

 sexual or not, effects the object of imparting rejuve- 

 nescence, and the ability to become cosmopolitan on the 

 part of those groups dependent on this method alone. 



As to whether the ascigerous fruit in the genus 

 Hypomyces is the result of a sexual act is not known, but 

 I have shown that its conidial phase, known as Mycogone, 

 has the vegetative cells binucleate, and further, that in the 

 conidium the two nuclei fuse. This is Dangeard's idea of 

 a sexual act; however, apart from this special point, the 

 fact remains that this method of rejuvenescence may 

 already exist in the conidial form of a species which yet 

 retains the older ascigerous form of fruit. 



If we once more contrast the evolution of chlorophyll- 



