[6] The most distinguishing feature of P. piliferum is the long, white awn at the tips of the leaves, which also give this moss its grey colour.

[2] Polytrichum piliferum has a bipolar, cosmopolitan distribution, occurring in suitable habitats on all continents[2][8] including Antarctica.

[14] Polytrichum piliferum grows close to the ground (about 4 cm or less) and forms dense clusters near the tip of the shoot, forcing the stem to be somewhat bare.

[3] In P. piliferum, shorter leaves are located close together towards the tip of its red stems, giving the shoot a characteristic tapered shape.

[6] The leaves of P. piliferum are costate and often stand erect, straight, and slightly in-curved when dry, and erect-spreading when moist.

[3] Polytrichum piliferum leaves possess parallel, longitudinal lamellae of photosynthetic tissue on their upper surfaces, which are a unique characteristic associated with the Polytrichopsida.

[16] The male shoots produce a dark-red, terminal antheridia[11] that is surrounded by a cup-shaped whorl of perigonial leaves that resembles a flower.