Sphagnopsida

A class of the plant division Bryophyta containing plants commonly called peatmosses. The spongelike plants grow as perennials in soft cushions or lawns in wet habitats (rarely they grow submerged). The class consists of a single genus, Sphagnum, of some 200 species. The thallose protonema, fascicled branches, dimorphous leaf cells, and spores developed from amphithecial tissue are characters unique to the class. The plants are ecologically important, owing to the spongelike construction of leaves and outer cells of stems and branches, and the ability, whether living or dead, to create acid conditions by exchanging hydrogen ions for cations in solution. The dried plant parts are used as a mulch in horticultural practice, and as fuel where the plant is abundant. See also Bryophyta.