266 



MORPHOLOGY. 



of pots in conservatories, mount it in water on a slip, with 

 the under side uppermost, we can then examine it for the 



Fig. 304. 



Male prothallium of a fern (niphobolus), in form of an alga or protonema. Sperniato- 

 zoids escaping from antheridia. 



sexual organs, for these are borne in most cases on the under 

 side. 



556. Antheridia. If we search among the rhizoids we see 

 small rounded elevations as shown in fig. 297 or 305 scat- 



Fig. 305. 



Male prothallium of fern (niphobolus), showing opened and unopened antheridia. , section 

 of unopened antheridium ; spermatozoids escaping ; spermatozoids which did tot escape 

 from the antheridium. 



