THE POLYTRICHACE.E OF WESTERN NORTH AMERICA 275 



12. Plants erect; marginal cells of lamellae not higher than wide, 



except in P. alpinum Pogonatum, p. 294 



12. Plants decumbent; marginal cells higher than wide. 



"Polytrichadelphus, p. 291 



CATHARINEA Ehrh. 

 Atrichum Beauv. 



Named after the Empress Catharine II of Russia. 



Plants not very tall. Stems with abundant rhizoids at base. 



Leaves without sheath, more or less transversely undulate, gener- 

 ally with diagonal rows of teeth on the back, mostly crisped when 

 dry. Margin plane, bordered except in young leaves, singly or 

 doubly serrate with coarse sharp teeth. Lamellae i-io, restricted 

 to the vein, composed of similar smooth cells, margin entire. Vein 

 f- the leaf-width or less, percurrent or vanishing, without lamellae on 

 the back, often toothed on back near apex. Cells all smooth, chloro- 

 phyllose, mostly quadratic, upper ones hexagonal or elliptic-hexa- 

 gonal. 



Calyptra naked, or with a few hairs or teeth at the tip. 



Capsule somewhat inclined, curved, never angular, smooth, with- 

 out stomates. Peristome present; teeth 32, pale, with yellow or 

 brown middle line. Lid long-beaked. Pedicel smooth, solitary or 

 sometimes 1-3 from a stem-tip. 



Number species in western North America, 4; total number 

 species, about 33. 



THE WEST NORTH AMERICAN SPECIES, A COMPARISON AND KEY. 



i . Capsule as 1 14 ; leaves not wavy along the margin when moist. 

 2. Vein constituting J-^ of the leaf -width. 

 3. Lamellae 1-2 cells high. 

 4. Cells .025-. 045. mm. 



5. Lamina without teeth at back /. C. crispa. 



i . Capsule as i : 6-8 ; leaves slightly to distinctly wavy along mar- 

 gins when moist. 



2. Vein constituting J-J of the leaf -width. 

 3. Lamellae 5-8 cells high. 

 4. Cells . OIO-.O2O mm. 



5. Lamina mostly with teeth at back 2. C. angustata. 



2. Vein constituting J-j | of leaf- width. 

 3. Lamellae 3-5 cells high. 



