This is a characteristic plant of good botanical quality short-grazed calcareous grassland, especially on chalk, but is also known from upland calcareous ledges and calcareous sand dune systems. When very happy it can grow as dense mats but is more usually found as scattered shoots, creeping though Festuca leaves in the company of other calcicolous bryophytes.
It is closely related to Thuidium, and when dry has the bright green colour, appressed leaves and stiffness of those species. Although not strictly complanate, the branches do seem to be in one plane. Unlike Thuidium species the branching is simply pinnate. Usually it is encountered dry as it prefers short, south-facing turf, but when moist the leaves are more spreading and the plant has a more bushy appearance.
There are two varieties recognised. Var hystricosa is the one usually encountered on the chalk. It has stem leaves > 1.5mm long and branch leaf cells > 1.5 times as long as wide. Var abietina is known from other habitats and has smaller stem leaves and shorter mid-leaf cells. Intermediates have been reported.Read the Field Guide account