This moss is readily recognised once known and is only likely to be confused with other members of the genus Polytrichum. Its stems are rigid and erect, with the long, pointed leaves arranged spirally around the stem, and at right angles to it, giving a star-like appearance when viewed from above. Groups of the plant can look rather like miniature conifer forests.

The genus name means "many-hairs" and refers to the hairy calyptra (or cap) which covers the capsule before it is fully mature. The genus shows probably the most complex internal differentiation of any group of mosses, having a relatively well-developed vascular (water and solute transport) system. The leaves are also remarkable in having on their upper surface columns of photosynthetic cells arranged in parallel longitudinal rows (lamellae). The species grows in a variety of habitats, always acidic, and including woods, heaths, wet moorlands, bogs. It is moderately pollution tolerant.