It is a small, gracile, semi-erect plant, with long and minutely-papillate internodes.

The leaves can reach a length of 24 mm, and are covered in bladder cells that have apically curving hair-like papillae.

Apically the leaves are slightly recurved, and each has a diadem of up to 16 yellow-orange bristles.

T. setuliferum can be distinguished from the other two by its papillate bladder cells; while those of the other two species are smooth and without papillae.

[1][2] Media related to Trichodiadema setuliferum at Wikimedia Commons