AbstractSphagnum isoviitae(sect.Cuspidata; theS. recurvumcomplex)sp. nov. is known by the brown and flat capitulum with a regularly 5-radiate appearance of the outer branches and the inner branches somewhat laterally curved and forming a delimited part, and a visible terminal bud; the acute-apiculate stem leaves longer than broad; the fairly narrow and usually 5-ranked divergent branch leaves which are nonrecurved or indistinctly recurved above when dry; the differentiated stem cortex; and the pale yellow spores. The new species is most closely related toS. fallax(Klinggr.) Klinggr. It grows in transitional poor and intermediate fens, and is reported from north-western Europe and eastern North America.