Plants robust, in bright green to yellowish green tufts, brownish tomentose proximally. Stems erect, simple, 4--8 cm. Leaves on sterile and female stems appressed, usually secund when dry, erect-spreading to falcate spreading when moist, 1.3--3 mm, plicate, ovate-lanceolate to lanceolate; margins revolute with paired teeth on mature leaves; costa very stout (to 600 µm wide at base), subpercurrent to short-excurrent, somewhat scabrous abaxially distally; laminal cells prorulose at proximal ends; distal laminal cells linear, 20--40 × 3--5 µm, basal cells shorter and broader, juxtacostal cells at widest part of leaf lax, pellucid and quite large (48--100 × 10--30 µm). Sexual condition dioicous; perigonia discoid. Seta to 4 cm. Capsule 2--3.5 mm. Spores subreniform, 22--25 µm, papillose.

A member of the Philonotis fontana complex, this essentially Old World species enters the flora area only in southern Greenland. Its distinguishing features include the falcate secund leaves, very stout costa, and lax, pellucid and quite large juxtacostal cells.