The Splachnobryaceae are a family of a single genus, Splachnobryum, consisting of 26 (Crosby et al. 2000) poorly defined species. Recent studies of the genus in Africa and Malesia have been published by Arts (1996) and Eddy (1996).  One species is recognized in the Americas.

            The taxonomic position of Splachnobryum is problematic. A. Koponen (1981) established the family Splachnobryaceae to accommodate this genus and placed the family in the Funariales, primarily on an interpretation of the peristome as being diplolepidous. Previously, Splachnobryum was maintained by some authors in the Splachnaceae where Müller (1869) originally placed the genus, essentially on the similarity of laminal cells. Other authors placed the genus in the Pottiaceae, based on the interpretation of its peristome as haplolepidous and its similarity to the genus Gymnostomiella (Vitt 1984, Zander 1993).  Norris and Zander (1981) argued, on the basis of rhizoidal insertion, that Splachnobryum belongs in the Pottiaceae.

Most evaluations of the peristomial pattern in Splachnobryum have been based on S. obtusum (Brid.) C. Müll. which has widely spaced, much reduced, and fragile peristome teeth. The peristomial pattern in this species is difficult to evaluate. Allen and Pursell (2000), using  a collection of Splachnobryum rostratum Broth. & Par. from Sierra Leone (Lewis s.n., MO)  with exceptionally well-developed, closely spaced peristome teeth found the species to have a 2:3 haplolepidous peristomial pattern. The relationship of the Splachnobryaceae to the Pottiales rather than the Funariales, is supported not only by its haplolepidous peristome, but also by its type of stomata and pattern of rhizoid insertion.

As noted above, Splachnobryum has sometimes been linked with Gymnostomiella Fleisch. The two genera have similar growth habits, textures, leaf shapes, areolation, and they both lack perigonial paraphyses. Gymnostomiella differs from Splachnobryum in having peculiar moniliform axillary hairs (i.e., with spherical upper cells), a well-developed stem central strand, papillose leaf cells, a very weak costa, and an eperistomate theca.