250 PHYLUM VIII. BRYOPHYTA 



tures whose interior cells produce sperms, which escape 

 from the antherid through a rent in its wall. Each 

 spermatogenous cell contains one spirally coiled sperm, 

 which, when set free, swims by means of its two long cilia. 

 442. The archegones are elongated, flask-shaped bodies 

 with a swollen base ("venter") and a long slender 

 neck. At maturity the neck has an open channel from 

 its apex to the base, where there is a rounded egg. In 

 some mosses the antherids and archegones are inter- 

 mixed in the same "flower," but in other cases they 

 occur upon different parts of the same plant ( monoe- 

 cious), or even upon different plants (dioecious). 



Fig. 125. — Antherids and Fig. 126. — Archegones and egga 



sperms (Sphagnum and (Sphagnum and Funaria). 



Funaria) . 



443. The act of fertilization requires water; but as the 

 sperms are very minute, a dewdrop may be sufficient. 

 The sperms swim to the open neck of the archegone, 

 down which they pass to the egg. The egg now begins 

 to divide rapidly, growing upward, eventually forming 

 the sporophyte. In most mosses the sporophyte is 

 narrow and elongated below, forming a stalk (seta) 

 which supports the upper spore-bearing part (the capsule 

 or spore-case). The epidermis of the latter is usually 

 provided with stomata, especially toward its basal part. 



444. The spore-case, when ripe, usually opens by a 

 lid which falls off, leaving a round opening, generally 

 fringed with many teeth. In most species as the sporo- 



