DEVELOPMENT OF PLANTS 



259 



contact with the tissues of the plant from which it absorbs nour- 

 ishment (Figs. 193, 194). The outer cell divides, forming a 

 spherical mass of cells that resembles the capsule of Ricciocarpus. 

 Some of these cells of the capsule develop as spore mother cells, 

 while others, known as elaters, elongate greatly and serve to con- 



Fig. 193. Germination of the gametospore : A, section of a mature 

 archegonium with canal cells dissolved, thus forming a passageway to the 

 large female gamete, g. B, sectional view of base of archegonium, show- 

 ing the germinating gametospore in two-cell stage. The perianth, p, is 

 seen growing up about the archegonium. C, later stage in the growth of 

 the gametospore. The lower cell shown in B is forming stalk cells, while 

 the outer cell has produced densely granular cells that will later by further 

 division form spore mother cells and elaters. 



duct the foods absorbed by the foot to the spore mother cells, and 

 finally they become spirally thickened (Fig. 194, C). During the 

 germination and growth of the gametospore, a delicate membrane 

 (the perianth) grows up about the archegonium and doubtless 

 assists the involucre in protecting it against drying winds (Fig. 

 I 93> P)- When the spores are mature, the cells of the stalk 



