This can be a confusing plant as it is so morphologically variable. Most problematically, its leaves may have hair-points or not, so confusion is possible with other species, particularly R. obtusum and R. affine.
In the field, it usually – but not always – forms compact cushions of narrow-leaved shoots that are unlike the typically lax tufts of the larger R. obtusum and R. heterostichum s. str. When it has capsules, a quick check of the inner perichaetial leaves will confirm that their shape differs little from the stem leaves.
The best ways of confirming R. sudeticum involve microscopic examination of leaves. Firstly, the nerve is typically 50 – 85um wide at the leaf base and therefore below the range of R. obtusum and R. heterostichum s. str. And, in transverse section, the shape of the nerve is conspicuously rounded on the dorsal side (underside of the leaf) and the upper part of the leaf is U-shaped.
For confident identification of this plant, Tom Ottley’s excellent key to British and Irish Racomitrium in Field Bryology is strongly recommended and can be downloaded from this page.Read the Field Guide account