A large moss, with long narrow leaves up to 1cm long, which are very undulate.  The leaves are erect above and spreading below, and are not very curved.  Under the microscope, the leaves are seen as strongly toothed in the upper part and with recurved margins below; the nerve is also toothed and there are two raised lines of cells at the back, best seen from a leaf section.  The stem is covered in dense white felty rhizoids. 

D bonjeanii

The growth habit, undulate leaves and mass of white rhizoids help to spot this in the field, but a leaf section should be made to check for the raised lamellae on the back of the leaf

Field and microscope photos are helpful, but we recommend that you retain a specimen for confirmation by an expert 

Acid soils.  Heathy woodland, mires and conifer plantations (British Bryological Society)

Scarce, but may be increasing (British Bryological Society)

rare

See the British Bryological Society webpage for this species