Plants brown, dark brown to nearly black. Branch leaves lanceolate to linear-lanceolate, apex narrow and tubular, hyaline cells with 8--12 moderate-sized (more than 0.25 cell diameter) in mostly one row.

Floating or stranded at margins of shallow lakes and ponds, rarely in seeps where probably constantly wet; Nfld., N.S.; Al., Ark., Del., Fl., Ga., La., Md., Miss., N.J., N.Y., N.C., S.C., Tenn., Tex., Va.