88 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull. 



7. Leaves smooth, eroso-denticulate at the apex 



Acaulon, p. 108 

 Leaves papillose, entire Phascum, p. 108 



8. Peristome, when present, with articulate teeth 9 



Peristome teeth not articulate 53 



9. Peristome present 10 



Peristome none 48 



ID. Leaves in 2 ranks, clasping at the base, and with a promi- 

 nent dorsal wing H 



Leaves in 3 or more ranks, not clasping at the base or 

 winged 12 



11. Plants flaccid, aquatic, floating Octodiceras, p. 105 



Plants not flaccid, sometimes submerged, but not floating 



Fissidens, p. 103 



12. Leaves with a single layer of small chlorophyll cells 



enclosed by two or more layers of large hyaline cells 



Leucobryum, p. 102 

 Leaves mostly with a single layer of uniform cells 13 



13. Peristome single, consisting of 16 or 32 teeth; teeth 



usually without a median longitudinal line on the outer 



surface 14 



Peristome double, the outer more or less thickened and 

 consisting of 16 teeth, the inner thin and divided into 

 segments or cilia or both; teeth with a distinct median 

 longitudinal line on the outer surface 33 



14. Capsule with 8 longitudinal ridges of differentiated cells 



Rhabdoweisia, p. 99 

 Capsule smooth or, when plicate, the epidermis of 

 uniform cell structure 15 



15. Peristome teeth with very minute longitudinal striations 



on the outer surface 16 



Peristome teeth without longitudinal striations on the 

 outer surface, smooth or papillose 19 



16. Alar cells large, hyaline or brown 17 



Alar cells not differentiated 18 



17. Leaves tufted; capsule distinctly strumose; monoicous. . 



Oncophorus, p. 99 

 Leaves regularly secund; capsule not strumose or ob- 

 scurely so; dioicous Dicranum, p. 100 



18. Lamina of leaves strongly papillose Dichodontium, p. 99 



Lamina of leaves smooth Dicranella, p. 98 



19. Peristome distinctly twisted, teeth 32 20 



Peristome not twisted, teeth 16, often deeply cleft 22 



