This is a common member of the community of ephemeral mosses in arable fields and disturbed sites than survive disturbance by persisting as tubers. It looks very similar to other small Bryums of similar habitats that typically form tufts of green shoots up to 1cm tall. The purplish rhizoids are usually visible in the field, but reliable identification requires microscopic examination. This is usually straightforward.
The rhizoids are generally smooth with a purple violet colour and the small spherical tubers (less than 40 microns wide) are produced in abundance. Bryum ruderale has purplish often papillose rhizoids with larger and fewer tubers.