This is one of the easiest mosses to recognize in the field. It is a robust, green or yellow-green plant with more or less regularly pinnate shoots to 10 cm or more long and relatively short branches (the shoots are therefore feather-like). The leaves are erect, loosely appressed and overlapping, only a little longer than wide and deeply concave. This gives the typically 2 mm wide shoots a stout, fat appearance. The leaves are about 2 mm long, broadly rounded or broadly pointed, and their most distinctive feature is the presence of a small, recurved point at the tip. At the tip of the stem and new branches, the crowded points of the leaves protrude like a miniature crown (older branch tips may become more attenuated). The leaves have a single nerve. Branch leaves are similar to the stem leaves, but a little smaller. Capsules are rare.

• robust and pinnately divided
• bright green to yellow green
• rounded, overlapping leaves
• leaves with a point at the tip, usually recurved
• at the shoot tip, the points on the crowded leaves forming a spiky 'crown'

P. purum occurs in a wide range of habitats, especially in unimproved, acidic grassland and heaths, but also in chalk and limestone grassland, on banks, among rocks and on rock ledges. It may occur in open woodland but not in deep shade.

Widespread and fairly common in Britain.

Fairly frequent in Leicestershire and Rutland.