FILICINE^ LEPTOSPORANGIAT.-E 



311 



(Fig. 157, A) is very peculiar. It has usually the form of a 

 funnel, whose upper rim is in contact with the wall of the 

 antheridium cell, and whose base strikes the basal wall of the 

 antheridium. Sometimes this first wall does not reach to the 

 base, in which case it is simply more or less strongly concave, 

 and the basal cell cut off by it from the antheridium is discoid 



Fig. 157. — Oiioclea stritthiopteris {YioKm). Development of the antheridium. A-C, Vertical sections, 

 x6oo ; D, two nearly ripe sperm cells ; E, free spermatozoid, X 1200 (about). 



instead of ring-shaped (Fig. 157, B). The second wall is 

 hemispherical, and is nearly concentric with the outer wall of 

 the antheridium. The dome-shaped central cell produces the 

 mother cells of the spermatozoids, and has much more dense 

 contents than the outer cells, but all the chloroplasts remain in 

 the latter. A third wall now forms in the upper peripheral 

 cell, much like the first one in form, and cuts off a cap cell at 



