P. inflatus is a large conspicuous terrestrial moss of higher altitudes. Plants form loose shiny yellow-green mats. The leaves are oval shaped with a short pointed tip, almost nerveless, and has undulate margins.  The alar cells at the basal corners of the leaves are inflated and orange colored.

P. inflatus is only known in a sterile form. Recent molecular data suggests that this moss is not related to members of the Pterobryaceae, and may eventually be accommodated in a family of it's own.