Four-toothed Mosses 



Perichatial 

 leaves. 



Leaf. 



Two teeth and curved spore-case Perigonium and 



margin. perigonial leaves. 



Tetradontium repandnm. 



Pedicel (seta). Thick and rigid. 

 Lid (operculum) . Conical, erect, short. 

 Teeth (peristome). Simple, of four short, triangular teeth. 

 Spores. Mature in autumn. 



Distribution. Near Glen House and at Dixville Notch, White 

 Mountains. Very rare. 



Genus SCHISTOSTEGA, Mohr 



The Genus Schistostega contains but one species; this is 

 found growing in bright-green patches on the ground in caverns 

 and grottoes and under the shade of rocks. The protonema is 

 persistent, and shines with a weird light in the semi-darkness 

 where it grows. The most striking character of the moss is the 

 highly refractive power of the protonema cells. These are able 

 to converge the feeble rays of light which enter the caves and 



Vertical section of a protonema to show paths of refracted 

 and reflected light rays; (5) an incident ray refracted to t, 

 then reflected from * to t and again reflected and refracted 

 T. repandum. Thread- from * to 5'; (v) clear cell contents; (c) chlorophyll grains; 

 like branch. (P) plasma. 



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