286 FRYE 



So named because the leaves are strongly incurved or twisted when 

 dry. 



Plants dioicous, loosely caespitose, glaucous green, reddish-brown 

 when old. Stems 1—3 cm. high, erect, rigid, simple. 



Leaves erect or spreading, lanceolate from an oblong base, more or 

 less acute; when dry strongly incurved and twisted but less crisped 

 and undulate than in Caiharinea. Margin not bordered, incurv'^ed 

 at least above thus making leaves somewhat tubular near tip, 

 remotely and minutely dentate at apex but sometimes entire. Lam- 

 ellae on upper side 10— 13, wavy from side to side, 6 — 12 cells high, 

 their margins variously notched and crested. Vein with 2 — 3 

 lamellae on back; back lamellae short, blunt, low, serrate, rather ridges 

 than lamellae, sometimes wanting. Cells hexagonal, rectangular at 

 base; cell- walls meeting margin of leaf perpendicularly. 



Cal5^tra with a few scattered hairs. 



Capsule ovate-cylindric, erect or somewhat inclined, somewhat 

 irregularly plicate when dry, contracted below the mouth, with 

 numerous stomates. Teeth short, unequal. Lid shortly rostrate, 

 oblique, often falling off with the calyptra. Pedicel smooth, rather 

 thick, 2—4 cm. long. — On soil. — Rogers Pass, Selkirk Mountain, 

 British Columbia; Greenland; Europe. 



COMPARISON OF VARIETY WITH TYPE. 



3. O. incurvum, t3'pical. 



I. Cells wall in upper half of leaf approaching leaf margin perpendicu- 

 larly. 

 2. Cells about midway between base and tip .010-.015 mm. in their 

 longer diameter. 

 3. Leaves usually remotely dentate, but sometimes entire. 

 4. Vein usually with 1-3 low serrate ridges or lamellae on back, 

 but sometimes smooth. 

 5. Capsule somewhat irregularly plicate. 



3a. O. incurvum var. latifolium^ (C. M. & Kindb). 

 Oligotrichum hercynicum var. latifolium C. M. & Kindb., Mac. Cat. 



VI, p. 149, (1892). 

 Oligotrichum integrifolium Kindb., in Revue Bryol. 1894, p. 40. 



^ Name derived from latum = broad, and folium = leaf; referring to the leaves 

 being broader than in the type. 



