12 SYNOPSIS OF BEITISH MOSSES. 



beak. Calyptra cucuUate. Colutnella persistent. 

 Spores small. 



Fam. 2. PottisB. 



L. smooth or more or less papillose, nerve terete. 



Calyptra cucuUate, rarely many-lobed, oblique. Caps. 



on a longer or shorter seta, erect. Perist. absent, or 



of 16 fragmentary or linear teeth, more or less perfect. 



34. Pottia, HJhr. Annual or biennial. St. simple 

 or slightly divided, radiculose below. L. broadish, 

 obovate-oblong, acuminate, opaque, smooth, or slightly 

 papillose, basal cells lax, hyaline, nerve smooth or 

 rarely lamellate. Caps, erect. Perist. absent, or if 

 present, of 16 plane teeth, generally imperfect; lid 

 rostrate or muticous. 



35. Didymodon, B. and S. Pereiinial. St. with 

 innovations below apex, sometimes dichotomous, radi- 

 culose at base of innovations. L. elongate and linear- 

 lanceolate, sheathing at base, apex more or less serrate, 

 cells lax, hyaline at base, smaller at apex, and densely 

 papillose. Caps, cylindric, symmetric, or arcuate, on 

 a long seta. Perist. t. plane, linear-lanceolate, confluent 

 at base, more or less cleft above, punctulate, rarely 

 papillose. Spores minute. 



Fam. 3. Triohostomaoese. 

 Csespitose or pulvinate. L. larger above, papillose, 

 apical cells minute, chlorophyllose, basal lax, dia- 

 phanous. Perist. t. united at base in a membrane, 

 more or less filiform above, papillose, crura equal or one 

 fragmentary, upright, oblique, or twisted. Spores 

 large and rough, or small and smooth. 



36. Trichostomum, B. and S. L. linear-lanceolate, 

 opaque, minutely papillose. Perist. t. with a narrow 



