Micrantheum serpentinum, commonly known as western tridentbush,[2] is a species of flowering plant in the family Picrodendraceae, and is endemic to north-western Tasmania.

Flowering occurs from September to early November and the fruit is a yellowish-black, oval capsule 3.0–3.3 mm (0.12–0.13 in) long with the remains of the styles attached.

[2] Micrantheum serpentinium was first formally described in 1991 by Anthony Edward Orchard in Aspects of Tasmanian Botany - a tribute to Winifred Curtis.

[3] Western tridentbush grows in shrubby, low, open woodland, shrubland or heath, usually on rocky hills sides in serpentinite geology, and is endemic to the Cradle Coast of north-western Tasmania.

The threats to the species include inappropriate fire regimes, land clearing, infestation by Phytophthora cinnamomi, and weed invasion.