376 PRACTICAL BOTANY 



MARCHANTIA. SPOROPHYTE 



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. 

 &. 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 



