Geniostoma petiolosum, commonly known as boar tree, is a flowering plant in the Loganiaceae family.

The inflorescences are clustered, 1–2 cm long, bearing 5–20 small flowers.

The ovoid-globose capsules, 6–7 mm long, contain small, black seeds in yellow pulp.

[1] The plant is endemic to Australia's subtropical Lord Howe Island in the Tasman Sea.

It is an uncommon inhabitant of sheltered forest throughout the Island, especially at lower elevations.