DEVELOPMENT. 



base, and this swollen part is called the apophysis (fig. io<r), 

 as in Splachnum ampullaceum ; this apophysis may be seen 

 at the base of the capsules of Polytrichum commune, but not 

 so exaggerated as in Splachnum; sometimes the swelling 

 is confined to a little bulging out of one side of the base 

 of the capsule, as in Dicranum falcatum, or in Dicranella 

 cerviculata, or Ceratodon purpureus, 

 &c.; the capsule is then said to be 

 strumose. 



The capsule is surmounted by a 

 membranous hood called the calyp- 

 tra, already mentioned as being 

 developed ifrom the upper portion of 

 the fertilized archegonium (fig. 11,2; 

 fig. 12, 3). In some genera, such as 

 the Bryums, this hood falls away 

 early, and hence is not seen upon 

 the mature capsule; but in many 

 other genera, such as Tortula, Hyp- 

 num, etc., it is persistent and may 

 readily be seen. In the act of sepa- 

 ration from the lower part of the 

 archegonium, or vaginula, the calyp- 

 tra is sometimes irregularly torn at 

 its base, as in Grimmia apocarpa, or 

 it may be evenly torn, as in Encalypta 

 vulgaris. In both cases the calyptra 

 is termed mitriform or mitre-shaped 

 (fig. n, 2). In many other mosses it 

 is slit up one side, and is then said to 

 be dimidiate (fig. 12, 3), (Lat, dimi- 

 dium, a half ), or it may be inflated, 



as in Funaria; and these characters are constant. Usually its 

 outer surface is smooth, but in some species it is papillose, 

 and in others more or less densely clothed with hairs, as in 

 Orthotrichum and Polytrichum. 



The mouth of the capsule is closed with a little lid called 

 the operculum, and between the lid and the mouth of the 

 capsule a ring of minute, highly hygroscopic ceils frequently 



FIG. 10. Splachnum am- 

 pullaceum. i, plant natural 

 size. 2, fruit enlarged ; a, 

 peristome ; b, cylindrical 

 capsule ; c, obovate apophy- 

 sis. 



