Treubia lacunosa is a species of liverwort in the family Treubiaceae that is found across New Zealand in moist shady areas on logs or soil.

The organism is relatively complex for a liverwort, and hosts endosymbiotic fungi which provide it with growth-inhibiting nutrients.

Two rows of lobes extend laterally outwards from this axis, and there are small upright lobules at the base of each.

One grows primarily in sheltered forest areas, while the other is found in more open and exposed habitats.

Molecular sequencing confirmed that there is a greater divergence between these populations than between other unrelated species, such as T. tasmanica and T. scapanioides.