102 



PLANT STRUCTURES 



and carries it upward perched on the top of the capsule like 

 a loose cap or hood (Eigs. 82, c, 107), which sooner or later 



falls off. As stated be- 

 fore, the mature struc- 

 ture developed from 

 the oospore is called a 

 sporogonium, a form of 

 sporophyte peculiar to 

 the Bryophytes. 



66. The sporogonium. 

 — In its fullest devel- 

 opment the sporogoni- 

 um is differentiated 

 into the three regions, 

 foot, seta, and capsule 

 (Figs. 82, 107) ; but in 

 some forms the seta 

 may be lacking, and 

 in others the foot also, 

 the sporogonium in this 

 last case being only the 

 capsule or spore case, 

 which, after all, is the 

 essential part of any 

 sporogonium. 



At first the capsule 

 is solid, and its cells 

 are all alike. Later a 

 group of cells within 

 begins to differ in ap- 

 pearance from those 

 about them, being set 

 apart for the produc- 

 tion of spores. This 

 initial group of spore-producing cells is called the arche- 

 sporium, a word meaning "the beginning of spores." It 



Fig. 85. Sporogonium of Fnnaria: A, an em- 

 bryo sporogonium (/,/*), developing within 

 the venter (b, b) of an archegonium ; B, C, 

 tips of leafy shoots bearing young sporo- 

 gonia, pushing up calyptra (c) and archego- 

 nium neck (h), and sending the foot down 

 into the apex of the gametophore. — After 

 Gokbel. 



