THE POLYTRICHACEZ OF WESTERN NORTH AMERICA 281 
Named after Selwyn.’ 
Plants dioicous. Stems more slender than in C. undulaia. 
Leaves undulate when moist, with transverse rows of teeth on the 
back, broader in proportion than in C. angustata, subspatulate, gen- 
erally obtuse, excavated at base. Margin bordered, serrate to mid- 
dle or below. Lamellea 4—6,9—13 cellshigh. Vein vanishing in 
apex, toothed at back. Cells .025—.050 mm. 
Calyptra quite smooth. 
Capsule nearly erect or subarcuate, narrowly cylindrical, dark pur- 
ple, shining, width to length about as 1:6—8. ‘Teeth shorter than 
in Cundulata. Lid shorter rostrate than in C. undulata.—On 
clayey soil and in crevices of rock.—Revelstoke, British Columbia; 
Rogers Pass and Beaver Creek in Selkirk Mountains, British 
Columbia; Lesser Slave Lake, Athabasca, Canada; Kootenai 
County, Idaho. 
OLIGOTRICHUM Lam. & DC. 
Name derived from oligo = few, and tricho = hair; referring to 
the almost naked calyptra. 
Plants dioicous. Stemssimple,1—3cm. tall, with rhizoids at base. 
Leaves not undulate, 1 cell thick; upper leaves lanceolate to ligu- 
late, when dry incurved-hooked and rarely crisped, when moist 
patent to squarrose from an indistinct sheath-like base, usually with 
lamella on back toward apex; lamina on back not toothed (except 
sometimes in O. parallelum). Margin not bordered, sometimes 
inflexed. Lameliz on upper side 3—13 (in our species), wavy from 
side to side (except in O. parallelum), with crenulate margins (except 
in O. parallelum), composed of similar smooth cells. 
Calyptra with a few erect hairs, rarely smooth. 
Capsule erect or inclined, symmetric, terete, oval or ovate, usually 
straight, smooth, with very large 2-celled stomates. Peristome pre- 
sent; teeth 32 (at least in ours), usually equal, pale throughout. Lid 
readily dropping off, thinly rostrate from a conic base. 
Number species in western North America, 3; total number spe- 
cies, about ro. 
3 Alfred Richard Cecil Selwyn, Director of the Canadian Geological Survey from 
1869 to 1895; editor of the Geological and Natural History Survey of Canada, anda 
jarge contributor to the same. 
