OK WESTERN PENNSYLVANIA. 27 



cells of stem-leaves usually weakly fibrillose in their upper 

 half, porose dorsally, the hyaline cells below non-hbrillose, 

 the pores large and few ; branches usually 4, one or two of 

 these very slender, pendent and rather closely appressed to the 

 >tem, the divergent ones horizontally spreading, with drooping 

 tips, rather swollen below, tapering towards the apex, the 

 branches often 2 cm. long; branch-leaves 2-3 mm. long, 

 broadly ovate, bluntly and cucullately short-pointed, the whole 

 leaf very concave and with more or less involute margins, 

 the apex dorsally scabrous by the erosion of the outer cell- 

 walls ; hyaline cells of the branch-leaves rather wide, spirally 

 fibrillose on both sides, with large well-defined pores of one- 

 third to one-half the cell-width and confined mainly to the 

 cell-angles; chlorophyllose cells in cross-section widely trape- 

 zoidal, the wider face being ventrally exposed and more than 

 or at least half of the width (dorsal-ventral) of the smooth 

 lateral walls, the dorsal face exposed and rather wide; the 

 cuticular cells of the branches porose and densely fibrillose: 

 fruit not seen. 



In bogs and swampy borders of ponds and streams. 

 Europe and in Xorth America from Canada to Florida. Quite 

 common in our region but mostly referred in the past to 

 S. cymbifolium. 



Beaver : Bog 1 mile north of Xew Galilee, Sep- 



tember 10, 1906. O. E. J. 



Center : In Rhododendron thicket along headwa- 



ters of Laurel Run. Tusseys Alt., July 15, 

 1909, and in open bog, Bear Meadows, 

 September 21, 1909. (Figured.) O. E. J. 

 Clearfield : Boggy woods, a few miles north of 



Cherry Tree, July 12, 1908. O. E. J. 



Crawford : In Tamarack bog near Linesville, May 12, 



1908. O. E. f. ; Bog near Mud Lake, 

 Hartstown, May 29-31, 1909. O. E. J. 

 and G. K. J. 



Jefferson : Miss Kate Stoy. 



Lycoming : Bog near Williamsport, July 16, 1908. 



O. E. J. 

 Mercer : Near Houston Junction, July 12, 1902. 



J. A. S. 



Westmoreland: Along small shaded stream, on Laurel 



Hill Mts., Mellon's estate, New Florence, 

 September 8-11, 1907. O. E. J. 



2a. Sphagnum affine forma squarrosula Warnstorf is a 

 strong growing form with the upper half of the leaves of the 

 branches when dry strongly squarrose. All gradations be- 

 tween the typical form and the squarrose form are to be found 



