Dacrydium guillauminii, commonly known as cat-tail Rimu or swamp Dacrydium, is a species of conifer in the family Podocarpaceae. It is found only in New Caledonia. It is a slow growing shrub or small tree with roots that grow in water, and reaches a height between 1 and 2 metres.

The species occurs on the banks of rivers and lakes in the south of Grand Terre, the largest island of New Caledonia. It is threatened by wildfires and habitat destruction. Its name honors the French botanist André Guillaumin, who spearheaded the study of the flora of New Caledonia.

...