Cryptomitrium is a genus of complex thalloid liverworts in the family Aytoniaceae.

The genus name means “hidden turban” in reference to the inconspicuous sheath around the immature sporangium.

[1] Sporophyte bearing receptacles are unlobed on  elongate, somewhat grooved stalks, which appear pale throughout or brownish purple near the base.

The receptacle is a convex-expanded disc, thinning towards the margins.

[1] Mature sporangia are brown, nearly spherical with very short seta, three to seven per receptacle, each opening by a lid-like operculum.