ADIANTUM PEDATUM. 129 



the peripheral protoplasm of the cell. The vesicle 

 attached to the hinder coils of the body is formed from 

 the central or intermediate contents of the sperm cell, 

 and usually contains some starch grains. 



The archegonium is likewise originally a single cell 

 of the prothallium, which by subsequent division forms 

 a central cell containing the oosphere, the two canal 

 cells whose destruction results in the formation of the 

 canal, the four rows of neck cells and the layer of cells 

 immediately surrounding the central cell. ** 



The conversion of the two canal cells into mucilage, 

 and the partial expulsion of this from the canal, 

 entangles and allows the entrance of the antherozoids, 

 which by their active movements work their way to 

 the base of the canal and penetrate the wall of the 

 central cell in which lies the oosphere. One anthero- 

 zoid bores its anterior end into the germinal spot of 

 the oosphere and disappears within it, probably reach- 

 ing the nucleus. The others lie for some time upon 

 the oosphere and are gradually absorbed, only one 

 antherozoid actually penetrating it. 25 



The result of the fertilization of the oosphere is the 

 formation of a new plant, which remains attached to 

 the prothallium on its under side for some time. As 

 the young fern gradually spreads sufficiently, and is 

 able by means of its leaf and root surface to gather 

 nourishment for itself, the prothallium, no longer use- 

 ful, perishes. 



84 Cf. Sachs, I.e. 



* 5 Strasburger, op. cit., p. 458. 



