OF WESTERN PENNSYLVANIA. 33 



Crawford : In tamarack bog one and one-half miles south- 

 east of Linesville, Tune 7, 1904, (Figured) and 

 June 12, 1905. O. E. J. 



8. Sphagnum recurvum Beauvois. 

 (.V. intermedium Hoffman; S. upicnlatniii Lindberg). 



(Plate II) 



Loosely but deeply tufted, pale green to greenish- or 

 whitish-yellow : stem light green, slender, long, in our region 

 often up to 3 dm. long, the cuticular sheath rather indistinct 

 and consisting of 3 or 4 layers of small or medium-sized rather 

 thick-walled cells; stem-leaves small, about 0.5-0.8(-1.0) 

 mm. long, equilaterally triangular to ovate-triangular, obtuse 

 and slightly erose-denticulate ; hyaline cells of stem-leaves 

 rather small, mostly non-fibrillose and non-porose, towards the 

 base on each side of the leaf more or less septate and narrowing 

 to form a very wide border, which abruptly narrows above but 

 reaches almost to the apex ; branches usually 4, t\vo very 

 slender and appressed-pendent, two somewhat larger and ir- 

 regularly spreading: cuticular cells of the branches elongate- 

 rectangular, perforate and somewhat recurved at the apex, like 

 those of the stem non-fibrillose ; branch-leaves lance-ovate, 

 imbricate, in our region ranging from 1-2 mm. long, when 

 dry, with undulate margins, flexuose and with a recurved apex, 

 when moist straight and erect-appressed, tapering to a rather 

 narrowly obtuse apex with two or three teeth, the margin in- 

 volute above ; hyaline cells of branch-leaves fibrillose and 

 porose, above the middle rather narrow, ventrally usually with 

 large pores in the cell-angles of about one-third the width of 

 the cell, dorsal ly with small end-pores or sometimes a very 

 few rather distinctly ringed lateral ones ; in cross-section the 

 hyaline cells are ventrally quite convex, the chlorophyllose 

 cells triangular or rarely trapezoidal, usually exposed only on 

 the dorsal face ; perichaetial leaves large, broadly oval, con- 

 cave, pointed : spores smoothish, yellow, about .025 mm. in 

 diameter. 



A cosmopolitan species occurring in Xorth America from 

 Newfoundland to Labrador and south to the Gulf States. In 

 our region quite common but perhaps mainly to be regarded 

 as belonging to the following variety: 



Sa. Sphagnum recurvum variety amblyphyllum ( Russow ) 



\\arnstorf. 



(S. amblyphyllum Russow). 



The variety has the stem-leaves more distinctly spatulate- 

 tiiantrular, with a more rounded and somewhat erose-denticu- 

 late apex ; the cuticular sheath is less plainly differentiated 



