324 



PELLIA. 



consisting of large cells nearly square in section, with 

 radial thickening bands ; (2) the inner wall layer, the 

 cells flattened and bearing numerous semi-annular thick- 

 ening bands ; (3) the elaterophore a tuft of spirally 

 thickened filaments (fixed elaters) springing from the 

 top of the seta and radiating into the cavity of the capsule, 

 which contains (4) the free elaters mingled with (5) the 

 spores. 



462. Structure of Sporogonium (Figs. 70-73). Mount 

 in water and examine (1) an entire capsule removed from 



its pocket and either 

 ruptured by being 

 pressed between two 

 slides, or teased open 

 with needles ; (2) a 

 ripe capsule which has 

 been carried up by 

 the elongation of the 

 seta and has dehisced ; 

 (3) a capsule valve 

 with its outer surface 

 uppermost. In these 

 preparations note 



(a) The enormous 

 elongation under- 

 gone by the cells of 



the seta, which in a few days will grow to about 40 

 times its original length, the cells losing their starch grains 

 in the process. 



(5) The elaterophore, a bundle of stout elaters fixed 

 by their lower ends to the top of the seta and consisting of 

 single elongated cells containing from one to three spiral 

 fibres. 



(c) The free elaters, with spiral fibres like the fixed 

 elaters but with both ends free and pointed these free 

 elaters are twisted irregularly and are mingled with 



(d) The spores, which (except in a quite young capsule) 

 are no longer unicellular but have germinated to form 



Fig. 72. PELLIA. The tip of a Capsule Valve, 

 seen from the outer side, showing the rod- 

 like thickenings on the outer layer of cells. 



