468 



BOTANY OF THE LIVING PLANT 



seen in the sexual organs of Pteridophytes. The antheridium 

 (Fig. 362, i.-viii.) is a club-shaped body, seated on a short massive 

 stalk, and it is frequently large enough to be seen by the naked eye. 

 It consists of a peripheral wall of tabular cells, covering a mass of 

 cubical spermatocytes (vi.). It bursts when ripe at the distal end 

 (viii.). There is often a special cap of mucilaginous cells, which produce 

 and control the pore of exit. The spermatozoids can then escape in a 



Fig. 363. 

 i.-v. Stages in development of the archegonium of Funaria, after Campbell ( x 4°°)- 

 vi. Mature archegonium of Andreaea, after Kiihn (X250). i. shows cover-cell 

 separated from central-cell (shaded), ii. iii. cover-cell (x) undergoing segmentation 

 as an initial cell, giving rise to three rows of lateral and one of basal segments : the 

 former constitute the " neck," the latter are the canal-cells, iv. shows the ovum (ov), 

 ventral canal-cell (v.c.c), and canal-cells {ex.). V. shows the apex of the neck before 

 rupture, with canal-cells {ex.) within. 



thin stream, embedded in mucilage from which they soon escape. In 

 cases where the perichaetial leaves face upwards, a shower of rain 

 would bring the rupture about, and the mucilaginous contents may 

 be seen and collected on a slide in a drop of water. The biciliate 

 spermatozoids may then be observed in active movement (Fig. 362, vii.). 

 The archegonium is a flask-shaped body with a long neck (Fig. 363). 

 It is seated on a massive stalk, and it also arises from a single superficial 

 cell. When mature it consists of a peripheral wall, which in the lower 

 ventral portion is double, but the neck consists of a single layer built 

 up of six rows of cells, as against four in the Pteridophyta. The wall 



