SECT. VH. 



SPORANGIA OF MOSSES. 



325 



summit, and leaving the lower part to form a kind of 

 collar round the base of the stalk. 



Fig. 48. Polytrichum commune: group of antheridia mixed with hairs and sterile 

 filaments (paraphyses), the central one discharging its contents. 



The urn-shaped organ or sporangium has a double wall, 

 and in its centre a fusiform or deeply winged columella. 



Fig. 49. Polytrichnm commune : B, cellular contents of an antheridium previously to 

 the development of the spermatozoids ; c, the same, showing the first appearance of 

 the spennatozoids-; D. the same, mature and discharging the spennatozoids. 



Between these two there is a tissue of a most delicate 

 texture, divided into spherical cells, each of which usu- 



