38 American Midland Naturalist Monograph No. 6 



much smaller dense cells which in turn surround a central core of larger 

 thinner-walled cells. Stem-leaves about 1-1.2 mm long, short-lingulate, often 

 almost as wide as long, the blunt broad apex partially erose-fimbriate, the 

 sides bordered above by a narrow margin of thick-walled linear cells, the 

 border widening at the base into a triangular patch, each patch about one- 

 fifth the width of the base; the upper middle hyaline cells about 3 times as 

 long as wide, non-fibrillose. Branches usually 4; two of them slenderly 

 attenuate and accumbent to the stem, the other two spreading, about 1.5-2.5 

 cm long, gradually acuminate, mostly spreading-falcate. Branch-leaves imbri- 

 cate and in the thicker part of the branch lanceolate to lance-ovate, about 1-1.4 

 mm long with the apex more or less squarrose-spreading, often involute tubular 

 and sometimes erose at the tip. Branch-leaves narrowly bordered, the median 

 cells ring-fibrillose and with many lateral pores between the fibrils. Chloro- 

 phyllose cells triangular-trapezoidal in cross-section, with the broader face 

 nearly flush with the upper (adaxial) surface of the leaf, the lower face 

 nearly enclosed between the strongly convex hyaline cells. 



Widely distributed in boreal regions extending south in North America to 

 New Jersey, West Virginia, Ohio, Minnesota, and Oregon. Reported by 

 Boehner as common in swamps and bogs in Cattaraugus County, southwestern 

 New York. 



Known/ from Elk, Fayette, McKean, Mercer, Somerset, and Tioga counties, in moun- 

 tain and upland swamps. Figured from sptecimen collected by Edmund W. Arthur, in a 

 wooded swamp. Swamp Root, Mercer Co., Sept. 20, 1946. 



20. Sphagnum Warnstorfii Russow 



(S. actttifolium var. gracile Russow) 



In swampy meadows, margins of bogs, etc., in Europe and, in North 

 America, from Greenland to Pennsylvania and westward to the Pacific States 

 and Alaska. The sp>ecies varies from bright green to yellowish or from red 

 to purplish. The green variety has been found in our region but once, its 

 characters being as follows, but it is doubtfully different enough to merit 

 varietal status. 



Crawford Co.: Pymatuning Swamp, Hartstown. O.E.J. May 29-30, 1915 (Det., 

 C.M.B.). Fayette Co.: Cranberry-sphagnum glade, 1 mi. w. of Markleyfburg P.O. 

 O.E.J, and C.M.B. Aug. 25, 1949. 



20a. Sphagnum Warnstorfii var. virescens Russow 



Plate VI 



Rather densely cespitose, bright green above, bleached or yellowish below: 

 stems in our specimens from about 5-12 cm high, the wood-cylinder green to 

 red and surrounded by a cuticular sheath of three layers of inflated cells, the 

 middle cells usually being the largest; stem-leaves about 1 mm long, broadly 

 lingulate, not auriculate, rather abruptly rounded to a narrow erose-dentate 

 somewhat concave apex, the margin very broadly hyaline-bordered below but 

 abruptly narrowing above and continuing rather narrow to the apex; hyaline 

 cells in upper half of stem-leaf broad, many of them once (or twice) septate, 



