INTRODUCTION. 



13 



behind (as is shown in fig. 14, where the perianth is 

 removed). In some genera where the colesule, or 

 perianth, is entirely or almost obsolete, as in Metz- 

 geria, the calyptra is more highly de- 

 veloped, and covered with rigid hairs (fig. 

 15). As the capsule rises on its own 

 peduncle it encloses within itself the 

 mature spores, mixed with spiral fibres, and 

 when the splitting takes place the spores 

 are discharged, together with some of the 

 elaters— whilst others remain attached to 

 the valves (figs. 17, 18). The exterior surface of 

 the four-valved capsule is often beautifully striate, 

 longitudinally and transversely (fig. 16). 



The elaters are elongated fusiform cells, with from 

 one to three spiral fibres coiled around the inner 

 wall. In some species the outer membrane is so 



16. 17. 18. 



delicate that it cannot be distinguished, but Gottsche 

 was of opinion that in all cases there was primarily 

 a cell membrane, within which the spirals of the 

 elaters were turned, although in some species it is 



