64 American Midland Naturalist Monograph No. 6 



Known from the following counties: Allegheny, Butler, Cambria (Porter), Fayette, 

 McKean, Washington, and Westmoreland. Specimen figured: Base of Tilia amerkana. 

 Brush Creek Swamp, Crider's Corner's, Allegheny-Butler county line, April 26, 1908. 

 O.E.J. 



6. DiCRANUM LONGIFOLIUM [Ehrhart] Hedwig 



{Paraleucobryum longifolium (Hedwig) Loeske) 

 Plate XIII 



Densely cespitose, pale green, glossy: stems more or less deeply castaneous, 

 ascending, geniculate at intervals, at least 3-5 cm long, sparingly brownish- 

 tomentose below; leaves lustrous, pale green, yellowish-green and hardly altered 

 when dry, falcate-secund, about 5-8 mm long, linear-subulate, from a short 

 lanceolate base about one fourth the length of the leaf, at the base reddish or 

 brownish, non-decurrent; costa wide, comprising about one-third the width of 

 the leaf-base, somewhat narrowed at insertion, the upper three-fourths of the 

 leaf consisting entirely of the linear-subulate, canaliculate, more or less spinose- 

 denticulate, excurrent costa; alar leaf-cells lax, rather thin-walled and hyaline, 

 sometimes brownish, rounded and extending to the costa, the laminal cells 

 immediately above with medium walls, obliquely oblong-angular, narrower 

 towards the margin and farther above becoming smaller and rhomboid-quad- 

 rate along the margin to elongate-rectangular near the costa: capsule cylindric, 

 erect, nearly straight, smooth, produced but rarely. 



On tree-trunks and on non-calcareous rocks in hilly or mountainous re- 

 gions, in Europe, Asia, and, in North America, from Greenland and British 

 Columbia south to Colorado and North Carolina. 



Rare in our region. McKean Co.: Bradford, 1896. Sterile. D.A.B. (figured). 

 Washington Co.: On root of beech tree near Washington. Dec, 1891. Linn Ac 

 Simonton. 



11. DiCRANODONTlUM Bryologia Europaea 



Dioicous: tall mosses mostly in dense tufts, the stems and often the basal 

 portion of the costa on the under side felted-radiculose: leaves weakly or not 

 at all auriculate, from the lanceolate base long-subulate, canaliculate-tubulose, 

 the acumen often plainly toothed on the margin and dorsal surface of the 

 costa by reason of the mammillate cells; costa broad and flat, long, excurrent, 

 and almost filling the acumen; alar cells reaching the costa, inflated, hyaline, 

 sometimes reddish, delicate, areolation above the alar cells widened towards 

 the costa and rectangular to long-hexagonal, at the margin usually united into 

 a more or less broad border; perichaetial leaves sheathing, abruptly long-subu- 

 late: seta arcuate, finally erect-flexuous; capsule symmetric, oblong-cylindric, 

 smooth; annulus not diff^erentiated; peristome inserted below the edge of the 

 capsule-mouth; teeth separate, two-parted deeply, or to the base, the divisions 

 filiform-subulate, below vertically and above obliquely striate-papillose; calyp>- 

 tra cucullate. 



A cosmopolitan genus of 21 species; 5 species in North America; 3 species 

 occurring in our region. 



