Papillose Sphagnum

Sphagnum papillosum Lindb. Acta Soc. Sci. Fenn 10: 280. 1872. sphagnum Waghornei Warnst. Hedwigia 33: 329. 1894.
Plants low, compact or slender to very robust, generally deeply tinged with brown to nearly black. Wood-cylinder brown to nearly black; cortical cells of the stem in 3-4 layers, their walls thin, with few and weak fibril-bands, the outer cells quadrilateral or somewhat irregularly shaped, often longer than wide, their pores rarely more than 1 or 2 in each cell, frequently small, always clearly defined: stem-leaves large, elongate-lingulate, or smaller and shorter, the toothed border narrowly hyaline toward the apex; hyaline cells frequently divided, without fibrils or more or less fibrillose, in the former case the membrane on the outer surface largely resorbed: branches in fascicles of 4 or 5, 2 spreading, their cortical cells in a single layer, with the basal walls plane; cellwalls generally reinforced inwardly by numerous fibril-bands, the outer wall often with a single large pore at the upper end: branch-leaves imbricate or slightly spreading, ovate, denticulate on the margin; hyaline cells fibrillose, rhomboidal, 3-5 times as long as wide at base, in the upper half 2-3 times as long as broad, on the inner surface with small ringed pores in the cell-angles, and often in the apical and lateral por tions of the leaf with large round pores in the central part of the cell, 1-5 per cell, on the outer surface with rounded or elliptic pores in the corners and along the commissures, 4-10 per cell, passing into large membrane-gaps in the short cells of the cucullate apex; chlorophyl-cells truncately elliptic or nearly lenticular in section, usually about equally exposed on both leaf-surfaces, the Wmen narrowly lenticular and more or less central; inner walls of hyahne cells where overlying chlorophyl-cells densely and finely papillose, the papillae sometimes reduced or lacking; hyaline cells somewhat convex on the outer surface, about one fourth of the diameter of the cell; resorption-furrow present.
Dioicous, rarely fruiting. Antheridial branches and leaves hardly differentiated. Fruiting branches erect; perichaetial leaves large, elongate-ovate, the upper region and border throughout of normal structure with hyaline cells fibrillose and porose, the central basal
portion of uniform elongate cells without fibrils or pores: capsule globose, brown: spores
yellow, about 2S m in diameter, papillose.
Type locality: Finland.
Distribution: Labrador southward to New Jersey; Vancouver Island; Alaska; reported from Indiana, Wisconsin, and Washington; also in northern Europe and Asia.