The Sporing of the Fern 253 



The first antheridia appear when the prothallus 

 is three or four weeks old. They are most often 

 formed toward the point of the heart, and are 

 scattered over its lower surface, apparently without 

 definite order. 



Each antheridium is, at first, a single cell pro- 

 truding slightly from the surface of the heart, and 

 looking deceptively like a young root-hair. 



Grown older, it is a little chamber, with a single 

 layer of cells forming its encompassing wall, and 

 with its interior packed quite full of tiny globes. 

 When the antheridium has reached fullest matur- 

 ity the cells, which wall in the little chamber, ab- 

 sorb water freely, swell, and burst open. 



The minute globes, which have been cribbed, 

 cabined, and confined, are now set free. Each 

 globe is what botanists call a "mother-cell," and 

 coiled up inside it lies 

 something which looks 

 like a* strap, with a nar- 

 rower and a broader end. 

 This is an " antherozoid " ^~ 



(Fig. 60). Soon after FlG - 6 9 .-Antherozoids of Pteris 

 '* serrulata. 



the mother-cell comes out < From the vegetable world.) 



of the antheridium it bursts, and the antherozoid, 



which has been lying in it, curled up and mo- 



