28 A MAXUAL OF .MOSSES 



in our region. A packet of specimens quite characteristically 

 of the squarrose form is as follows : 



Cambria: On boggy plateau near St. Lawrence, July 24, 

 1908. O. E. J. 

 (Mixed with S. recurvum Schwaegrichen). 



3. Sphagnum latifolium Hedwig. 

 {S. palustre Linnaeus; S. cynibifoliuin Ehrhart). 

 (Plate I) 

 Densely cespitose, usually robust, bluish or glaucous- 

 green to yellowish: stems rather stout, usually 8-10 cm. long, 

 sometimes 2-3 dm. long, the cuticular sheath composed of 

 3-4 layers of inflated cells, the innermost of which are the 

 largest, the outer layer being rectangular, fibrillose and porose, 

 the wood-cylinder being usually yellowish or brownish ; stem- 

 leaves large, about 2 mm. long and 1.25 mm. broad, sometimes 

 3 mm. long, spatulate-lingulate, the broadly rounded apex 

 somewhat erose-fimbriate, below narrowly hyaline-bordered, 

 the insertion composed of brownish and incrassate cells ; lower 

 hyaline cells of stem-leaves sometimes septate, non-porose, 

 non-fibrillose, those of the upper one-half or two-thirds of the 

 leaf fibrillose and porose as are the branch-leaves also, towards 

 the apex the hyaline cells much broader relatively, often as 

 broad as long; branches in different plants variable, 1-2.5 

 cm. long, more or less turgid below, acutely tapering at the 

 apex, usually two spreading with drooping tips and two 

 pendent and closely appressed to the stem, the comal short, 

 ascending, more or less blunt; the branches in cross-section 

 showing a layer of inflated cuticular cells which are rectangu- 

 lar, porose, and fibrillose ; branch-leaves usually about 2 mm. 

 long, sometimes 3 mm., widely ovate, very concave, the mar- 

 gins involute, the apex abruptly and bluntly tapering, cucul- 

 late, at back somewhat scabrous with the erosion of the outer 

 cell-walls, when dry the leaves being" more or less closely 

 imbricate ; hyaline cells of branch-leaves broad, fibrillose, 

 ventrally porose with large lateral pores mainly confined to 

 the cell-angles, the pores often equalling one-third the width 

 of the cell, dorsally the pores somewhat smaller and more 

 elliptic and lateral, mostly in the cell-angles ; in cross-section 

 the chlorophyllose cells are narrowly barrel-shaped or some- 

 what trapezoidal, exposed on both faces, being ventrally nearly 

 flush with the ventral surface of the hyaline cells but the latter 

 dorsally very convex and projecting much beyond the chloro- 

 phyllose cells, the lateral walls of the chlorophyllose cells 

 smooth; perichsetial leaves very large, broadly oval, cucullate, 

 hyaline-bordered, rounded obtuse at apex : capsule at maturity 

 considerably exserted above the comal tuft; spores yellow, 

 .028-.033 mm., mature in mid-summer. 



