Physiology of Antheridium Formation in Ferns 72^ 



Dr. Niif: Preliminary investigations are in agreement with the 

 hypothesis that archegonium formation is also under the control of 

 a demonstrable factor, although it is probably not secreted into the 

 medium. The experimental results as well as certain theoretical con- 

 siderations further indicate that this factor can be demonstrated only 

 if it is assayed against the prothalli of species which have special 

 characteristics with regard to archegonium formation. I should like 

 to emphasize that many more experiments will be required before 

 this can be considered established. The Pteridium factor is quite 

 stable. Specifically it is stable to autoclaving at the pH of the medium 

 and to boiling for 10 min. at pH 2, but labile to boiling for the same 

 length of time at pH 12. 



Dr. Morel: When an adult gametophyte is cut into small pieces 

 and put into a medium, it regenerates new gametophytes. What is 

 the situation with this new gametophyte; is it the same as when you 

 start with a spore? 



Dr. Naf: I cannot give a definitive answer to this question because 

 this problem has not been thoroughly investigated. Some incidental 

 observations suggest, however, that the situation in regenerating 

 gametophytes is the same as in gametophytes grown from spores. 



