Crimson-tuber Thread-moss is quite small and delicate for a Bryum. Shoots are usually no more than 1 cm tall; occasionally up to 1.5 cm. Stems are often reddish, and the leaves (about 2 mm long) may be slightly tinged red. Rhizoids are reddish-brown. Capsules are 2 mm long and frequent. The bright red tubers (white when young) are the best clue to identifying this moss in the field, and usually occur at the base of the lower leaves. Tubers also grow on the longer rhizoids (especially in plants not found in arable fields), and can be seen by crumbling the soil in which the plants are growing. These tubers are about 0.25 mm across, bright enough to be just visible to the naked eye, and become very obvious when viewed through a hand lens.

This moss grows on bare soil in a wide variety of places such as arable fields, waste ground, patches of soil amongst grass in fields and gardens, and beside roads and paths.

All year round.

Widespread and fairly frequent in Britain, the more local in Scotland.

Status in Leicestershire and Rutland not known.