MUSCI. •> 



15. Trichostomum. Peristome of 16 or 32 teeth, in pairs. 

 Calyptra campanulate, shorter than the mature capsule. 



16. Glyphomitrion. Peristome of 16 teeth, in pairs. Ca- 

 lyptra campanulate, longer than the mature capsule. Capsule 

 destitute of an apophysis. 



17. Dicranum. Peristome of 16 equidistant bifid teeth. Ca- 

 lyptra dimidiate. 



18. Tortula. Peristome of 32 teeth, ,spirally twisted above, 

 united more or less below into a tubiform membrane. 



19. Zygotrichia. Peristome of 32 teeth, in pairs, spirally 

 twisted above, united below by transverse processes. Calyptra 

 dimidiate. 



20. Cinclidotus. Peristome of 32 teeth, spirally twisted 

 above, united below by transverse processes. Calyptra cam- 

 panulate. 



21. Polytrichum. Peristome of 32 or 64 equidistant teeth 

 united at their tops by a horizontal membrane. Calyptra dimi- 

 diate, minute. 



ft 



Peristome double. 



A. 



Inner peristome composed of distinct teeth or cilia. 



(Sometimes wanting in Entosthodon and Orthotrichum. ) 



22. Entosthodon. Peristome oblique ; outer of 16 horizon- 

 tal teeth from the inner membrane of the capsule ; inner obso- 

 lete or wanting. Capsule with an apophysis. 



23. Funaria. Peristome oblique; outer of 16 teeth; inner 

 of as many cilia opposite to the teeth. Capsule pyriform, its 

 mouth oblique. 



24. Zygodon. Outer peristome of 16 teeth, in pairs; inner 

 of 8 or 16 cilia. Calyptra dimidiate. 



25. Orthotrichum. Outer peristome of 16 teeth in pairs; 

 inner of 8 or 16 cilia. Calyptra campanulate, sulcate. 



B. 



Inner peristome, a membrane divided above into lacinice or seg- 

 ments. 



26. Bryum. Outer peristome of 16 teeth ; inner of 16 equal 

 lacinice, frequently with filiform processes interposed. Calyptra 

 dimidiate. 



27. Bartramia. Outer peristome of 16 teeth ; inner of 16 

 equal bifid lacinice. Calyptra dimidiate [capsule mostly globose.) 



