OF WESTERN PENNSYLVANIA 83 



Lawrence : Gorge below EUwood City, June 26, 



1909. O. E. J.; October 15. 1910. O. E. 



J. and G. K. J. 

 McKean : Hawkins Hollow, Bradford. August 2, 



1895. D. A. B. 

 Westmoreland : Rachelwood, New Florence, September 



8-11, 1907. O. E. J. (Figured.) 



5. Fissidens exiguus Sullivant. 



(Plate XI) 



Plants very small, gregarious, light green : stems, in our 

 specimens, 1-2.5 mm. high, erect, or ascending; leaves usual- 

 ly 3-5 pairs, the lower minute, the upper reaching 1.5 mm. 

 long, ascending to erect, oblong-lanceolate, acute, only the 

 sheath margined, entire, the dorsal lamina narrowing to none 

 at the base, the sheath about one-half the length of the leaf; 

 costa stout, vanishing a little below apex ; cells in apical lamina 

 quadrate to hexagonal, at base of leaf becoming rectangular, 

 the sheath being bordered, especially in its upper part, by a 

 border one to four cells wide, of elongate and more or less 

 prosenchymatous cells, all cells moderately incrassate or more 

 so in border of sheath : capsule on an erect, somewhat flexu- 

 ous. stout, reddish pedicel 2-5 mm. long; capsule oblong-oval, 

 narrowed to pedicel at base, somewhat constricted below 

 mouth, smooth, reddish-yellow, about 0.5-0.7 mm. long; 

 operculum conic-rostrate, about two-thirds the length of the 

 capsule ; calyptra narrow, dimidiate ; teeth red, split to the 

 middle into two awl-like prongs which have spiral thicken- 

 ings, closely infolded in wet specimens, inserted a little below 

 edge of mouth ; spores smooth, about .020 mm. in diameter. 

 Mature in September. 



Rather common on stones and rocks in stream beds, es- 

 pecially in ravines. Southern Canada, United States east of 

 the Rockies, England. 



Allegheny : On sandstone rocks, ravine of Powers Run, 

 November 30, 1909. O. E. J. 



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



J. and G. K. J. (Figured.) 



6. Fissidens cristatus Wilson. 

 (F decipicns De Notaris). 



(Plate XI) 



Usually tufted, branching from the base, green to dark 

 gi een ; stem erect, 1-2 cm. high ; leaves numerous, ascending, 

 imbricate, the upper reaching 2.5 mm. long, oblong-lingulate, 

 acute, crenulate below, irregularly serrate above, inferior 

 lamina narrowed and somewhat decurrent at base, sheath ex- 



