Jennings: Manual of Mosses — 2. Dicranaceae 59 



1. Oncophorus Wahlenbergii Bridel 



Plate XII 



Densely cespitose, light or yellowish-green above, darker below: stem 

 ascending or erect, forking, up to 3 cm high, sparsely radiculose below; leaves 

 numerous, dense, much crisped when dry, abruptly flexuous-spreading when 

 moist, from a concave, widely obovate base abruptly contracting into a long, 

 carinate, linear-subulate, flexuous, rather acute portion which is low-serrate at 

 the apex both marginally and dorsally; costa strong, ending in the apex; leaf- 

 cells at base mostly pellucid and obliquely elongate-rectangular, about 3-10:1, 

 above at the shoulder and along the subulation quickly becoming much smaller, 

 incrassate, about .005-. 007 mm in diameter, smooth, sometimes faintly rounded 

 papillose: seta single, erect, flexuous, yellowish to brownish, when dry strongly 

 dextrorse, 1-1.5 cm long; capsule about 1.2 mm long, arcuate-cernuous, oblong- 

 cylindric, gibbous, distinctly sharply strumose, when old irregularly wrinkled; 

 peristome-teeth united at base into a rather deeply inserted tube, the teeth divid- 

 ed to the middle, lance-linear, castaneous-pellucid, very faintly dorsally articulate 

 below, strongly ventrally trabeculate in a double series separated by a more or less 

 zig-zag divisural line, at the base smooth, towards the middle minutely vertically 

 striate-papillose, at the apex sub-hyaline; annulus narrow with crenulate margin; 

 operculum obliquely rostrate; exothecial cells irregular, rather lax, with medium 

 walls, not much different towards the mouth; spores papillose, castaneous- 

 pellucid, about .028-. 030 mm, mature in spring. 



On rocks, soil, or mostly on old logs, in cool and moist situations, usually 

 in the mountains in non-calcareous districts. Europe, Asia, and, in North 

 America, from Greenland to Alaska and south to Pennsylvania and Ohio; 

 and Wyoming. 



Rare in our region. McKean Co.: Broadbow, D.A.B. (figured.) 



10. DiCRANUM Hedwig 



Autoicous or dioicous; mostly large and thickly tufted, often cushion-like: 

 stems mostly erect; leaves mainly falcate-secund, more or less subulate-acu- 

 minate from a concave, lanceolate base, and usually canaliculate to tubulose; 

 costa largely excurrent; alar leaf-cells mostly brownish and differentiated; inner 

 perichastial leaves elongate, involute-sheathing, the acumen often short or lack- 

 ing: seta erect, mostly twisted, sometimes 2 to 5 together in a pericha?tium; 

 capsule various from cylindric and erect to cernuous and arcuate or even rarely 

 strumose; operculum long-rostrate and by a differentiated annulus always 

 with a notched edge; peristome not inserted below the edge of the capsule; 

 teeth mostly 2-3-parted to the middle, vertically striate below, ventrally trabe- 

 culate; calyptra not ciliate at base. 



A cosmopolitan genus as here treated of about 150 species, mostly on non- 

 calcareous sub-strata, in the tropics confined to the mountains and rather rare 

 in. the Southern Hemipshere. In North America about 40 species are known 

 and at least 6 species occur in our region. 



