The tightly packed shoots of this species form light green tufts 2–6cm tall, usually with abundant capsules.
The leaves are 3–5mm long with a smooth margin (entire). They are drawn out to a long, thin wavy tip (ovate-lanceolate).
Upright, cylindrical capsules are borne on a long, thick seta up to 3 cm long, and have a conspicuously long, thickened neck.
T. mnioides resembles Tetraplodon angustatus but can easily be distinguished as T. angustatus has
Splachnum species have more shortly pointed leaves. Their capsules have different shapes and are borne on a more slender, often wavy, seta.