SPORE-CAPSULES AND PERISTOME OF MOSSES. 351 



(although grafted on to these, and drawing their nourishment 

 from them), are closed at their summit by opercula or lids (Fig. 

 135, B, o, 0), which fall off when the contents of the capsules are 

 mature, so as to give them free exit ; and the mouth thus laid 

 open is surrounded by a beautiful toothed fringe, which is termed 

 the peristome. This fringe, as seen in its original undisturbed 

 position, is shown in Fig. 136 ; whilst in Figs. 137-139 are shown 



FIG. 136. 



FIG. 137. 



Mouth of capsule of Funaria, showing the 

 Perislome in situ. 



Double Peristome of Fontinalis 

 antipyretica. 



three different forms of it, spread out and detached, illustrating 

 the varieties which it exhibits in different genera of Mosses, 

 varieties whose existence and readiness of recognition render 

 them characters of extreme value to the systematic Botanist, 

 whilst they furnish objects of great interest and beauty for the 



FIG. 138. 



FIG. 139. 



Double Peristome of Bryum 

 intermedium. 



Double Peristome of Cindidium 

 arcticum. 



Microscopist. The peristome seems always to be originally 

 double, one layer springing from the outer, and the other from 

 the inner, of two layers of cells which may be distinguished in 

 the immature capsule (Fig. 135, c,jo); but frequently, at the time 

 of maturity, one or other of these is wanting, and sometimes 



