THE SPOROPHYTE OF THE MOSS 



299 



I 7 



aquatic life. The archegonia (Fig. 268, B) have very long necks, 

 and the relatively small egg lies at the bottom as in a flask. 

 The sperms are attracted to the 

 mouth of the open archegonium by 

 substances in the mucilage within 

 the neck, one of which at least is 

 sugar. They swim down the neck 

 to the egg, and one of them fertil- 

 izes it. 



296. The sporophyte of the 

 moss. The sporophytes of some of 

 the common mosses are the most 

 complex found among the bryo- 

 phytes, with the possible exception 

 of those of Anthoceros. There is 

 generally a long stalk which bears 

 a large spore case (Fig. 269, A). The 

 structure of the spore case is very 

 elaborate. A cover (operculum) is 

 formed at the end, which falls off 

 so that the spores may escape from 

 within. In many mosses the cover 

 is loosened and thrown off by an 

 interesting mechanism, which is 

 sometimes very highly developed. 



There may be a circle of cells with FlG - 268 ' Section throu g h the 

 ,, . , . .._ , tip of a female plant of a moss 



thickened and otherwise modified (Funaria) 



cell walls, forming a well-defined 

 ring (Fig. 269, A, r) around the spore 

 case underneath the cover. These 

 cells change their form when w r et, 

 sometimes swelling greatly (Fig. 

 269, (7), and thus loosen or tear the cover away from the spore case. 

 The rim of the opening formed when the cover falls off is 

 surrounded by a circle of pointed triangular structures called 



A, group of archegonia a: ,leaf. B, 

 an archegonium in detail, show- 

 ing enlarged basal portion e with 

 the egg, and the neck n above with 

 its row of canal cells: m, mouth. 

 After Sachs 



