33 



34 



•'T"' 



--nrv- 



36 



Figs. 33-36. — Some features of the life-history of a fern: Fig. 33, a 

 sporangium containing spores; Fig. 34, young prothallium (gameto- 

 phyte) arising from the germination of the spore (shaded), which is still 

 visible at the bottom; Fig. 35, mature prothallium, showing the female 

 organs (archegonia) at the top (/) and male organs (antheridia) at the 

 bottom (w); Fig. 36, a section of a single archegonium, showing the 

 egg (e) immediately above it, the ventral-canal cell, and above this 

 the neck-canal cell with two nuclei. Highly magnified. 



