47 



sporogonium, or spore capsule, and the hypobasal 

 cell the short seta or stalk. 



(2) The first division is followed by two others at 

 right angles to it and to each other, so that the 

 embryo now consists of eight cells. 



(3) Subsequent divisions take place more irregu- 

 larly, and the seta and the sporogonium 

 become differentiated. 



a. The Seta is a short stalk consisting of a mass 

 of squarish cells. 



b. The Sporoijonium exhibits three sets of 

 tissue : — 



i. The Wall, which consists of a single 

 layer of flattened cells. 



ii. The Elaters. Long cells, which taper at 

 both ends and are thickened by from one 

 to three spiral bands. 



iii. The Spore Mother Cells, which are ar- 

 ranged in rows between the elaters. 



The sporogonium is thus a shortly-stalked ball, 

 enclosed in the female sexual organ ; it is des- 

 tined exclusively for the production of spores. 

 It is not organically united with the previous 

 generation, but is nourished by it. 



(4) "While this has been going on, the neck of the 

 Archegonium first closes and then shrivels up 

 and becomes brown, and the Calyptra increases 

 in size to accommodate the large sporogonium. 



