Plants moderate-sized to often quite robust, ± weak-stemmed, lax; green, bluish green, green and brown to dark golden brown, often speckled in appearance; found submerged in shallow water, stranded along shore lines in loose carpets. Stems brown, superficial cortical layer with spiral reinforcing fibrils clearly visible, usually many pores per cell (1-6), comb-fibrils on interior wall. Stem leaves 1.1 × 1 mm; rarely hemiisophyllous; hyaline cells non-ornamented, frequently septate. Branches clavate and rounded at distal end. Branch fascicles with 2 spreading and 2 pendent branches. Branch stems with hyaline cell comb-lamellae visible on interior cortex wall, cortical cell end walls with conspicuous funnel projections more than 1/2 length of cell, superficial cortical wall aporose. Branch leaves broadly ovate, 2.4 × 1.7 mm; hyaline cells on convex surface with numerous round pores along the commissures, comb-lamellae on hyaline cell walls where overlying chlorophyllous cells; chlorophyllous cells broadly triangular in transverse section and well-enclosed on the convex surface. Sexual condition dioicous. Capsule with pseudostomata. Spores 22-29 µm; finely papillose on both surfaces; indistinct triradiate ridge on distal surface; proximal laesura 0.5-0.6 spore radius.
Stream channels, shallow ponds, coniferous and hardwood swamps and pocosins; low to moderate elevations; Ala., Fla., La., N.J., N.Y., N.C., S.C., Tex.; Mexico; West Indies; South America.
Sphagnum portoricense is normally very easily distinguished because of its wet growing habit and strongly clavate branches.