MAKCHANTIA. SPOROPHORE. 33 



XVII. Cut median longitudinal sections of a female 

 receptacle bearing almost mature sporogonia : mount as 

 before, and note under a low power that the parts of the 

 receptacle remain as before : but observe especially 



1. The perigynium, a loose sac-like coat, which 

 arises from the receptacle after fertilisation, and enve- 

 lops the archegonium during its further growth. 



2. The wall of the archegonium, now consisting of 

 two layers of cells, and still bearing at its apex the 

 neck, which shows signs of withering. 



3. The sporogonium, an almost spherical body 

 inclosed by the enlarged venter of the archegonium : 

 the following parts of it are to be recognised 



a. The massive conical foot or seta at the end 



remote from the neck, i.e. directed towards 

 the base of the archegonium. 



b. The wall of the remaining portion of the 



sporogonium (capsule), consisting of a 

 single layer of cells. 



c. The hemispherical sporogenic mass, with no 



central columella : in it may be recognised 

 (i.) the elaters, long spindle-shaped cells, 

 arranged in a fan-like manner as seen in 

 section ; and (ii.) the spores. 



Mount a small portion of the yellow flocculent mass 

 which escapes on the rupture of a mature sporogonium, 

 and breathe gently on it, observing it the while under 

 a low power : note the hygroscopic movements of the 

 spirally thickened elaters, and the consequent separation 

 and scattering of the spores. 



Sections should also be cut through female receptacles of various 

 ages, and by a comparison of these the development of the 



D 



