OF WESTERN' PENNSYLVANIA. 57 



Cheat Haven. September 3-6, 1910. O. E. 



J. and G. K. J. 



Lawrence : New Castle, 1906. Miss Susan Gageby. 



McKean : Toad Hollow, Bradford, June 17, 1896, and 



Bennett, May 30, 1897." D. A. B. 



Washington : Spier Station, May 20, 1907. O. E. J. 

 Westmoreland: Laurelville, May "30-31, 1903. ]. A. S. ; 



Blackburn, June 13, 1908. (Figured). 



5. CERATODOX Bridel. 



Dioicous. rarely autoicous ; cespitose. green to brown or 

 reddish-brown, somewhat radiculose ; stem 3-5-angled, with 

 a central strand, thickly foliate, often bushy-branched ; leaves 

 erect-spreading, appressed and more or less twisted when dry, 

 ovate to lance-linear, neither sheathing nor subulate-pointed, 

 margin revolute ; costa strong, percurrent or long-excurrent. 

 with median guides ; leaf-cells thick-walled, short-rectangular 

 below, the upper quadrate to rounded, smooth : perichaetial 

 leaves distinctly sheathing; seta long and erect; capsule in- 

 clined to horizontal, elliptic-ovate to oblong, purplish to red- 

 dish-brown, shining, when dry silicate; annulus spirally decidu- 

 ous. 2- -4-seriate ; peristome-teeth 16. cleft nearly to the base 

 into filiform divisions, united at the base into a tube, the 

 teeth closely articulated below, less closely above, papillose ; 

 operculum conic, much shorter than the capsule ; calyptra 

 cucullate. 



.-V cosmopolitan genus consisting of 27 species ; 7 species 

 in Xorth America, only one occurring in our region. 



1. Ceratodon purpurascens (Hedwig) New Combination. 



(Mnium pnrpiircum Linnaeus; Dicranum purpnrascciis Hedwig; 

 Ceratodon pnrpurciis Bridel). 



(Plate VI] 



Densely and often rather deeply brownish- or reddish- 

 cespitose, mostly green above and dark brown below: stems 

 mostly branched, erect, about 1 cm. high, dying away below; 

 leaves lanceolate to linear-lanceolate, carinate, the margin* 

 revolute to near apex ; costa strong, percurrent, at base about 

 one-sixth to one-fourth the width of the leaf; seta about 1.5 

 cm. long, erect, dark-castaneous. lustrous, twisted when dry; 

 capsule oblong-linear, at first erect, later inclined to horizontal 

 and more or less curved, irregularly silicate, strumose, about 

 2.5 mm. long, dark red-brown, lustrous, annulus distinct, re- 

 voluble ; peristome-teeth dark red below, basally confluent, 

 papillose, weakly trabeculate to a little above the middle, bor- 

 dered, hyaline above; operculum conic-elongate, about one- 

 fourth the length of the urn, often somewhat curved, usually 

 darker brown than the urn ; calyptra cucullate : exothecial cells 



