SPOROGONIUM OF MOSSES. 



353 



ceases^ its surface is occupied by two or three layers of yellow to 

 reddish-brown strongly-thickened cells, the cavities of which, as 

 we pass inwards, become gradually larger. In the interior of 

 the seta a central conducting bundle is differentiated. The 

 stomata upon the apophysis of Funaria hygrometrica are of 

 interest in that the division of the mother-cell, so as to form 

 the guard-cells, is incomplete. Hence there is but one guard- 

 cell, shaped like a ring, with a short median cleft. In the early 



FIG. 129. Mouth of the capsule 

 of Fontincdis antipyretica, the 

 operculum having fallen off. op, 

 outer peristome of teeth ; ip, inner 

 peristome of cilia (x 54). (After 

 Sachs. ) 



FIG. 128. Fuiuiria hygrometrica. A , a young leaf- bearing plant (g), with the 

 calyptra (c). B, a plant (</) with nearly ripe sporogonium ; s, its seta ; /, the 

 capsule ; c, the calyptra. C, longitudinal section of the capsule bisecting it sym- 

 metrically ; d, the operculum ; , the annulus ; p, the peristome ; c, c, the colu- 

 mella ; h, the air-cavity (which here extends around as well as below the spore-sac) ; 

 s, the spore-layer, consisting of the primary mother-cells of the spores ( x about 

 20). (After Sachs.) 



stages of development the dividing wall was complete, but its 

 ends are subsequently resorbed. 



The accompanying Figures 128 and 129 will serve further 

 to elucidate the foregoing description of the structure of the 

 capsule in mosses. It should be noted that the descriptions are 

 confined to Bryaceae, just as in the Liverworts they were re- 

 stricted to the Marchantiaceae. 



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