Pisonia grandis, the grand devil's-claws,[1] is a species of flowering tree in the Bougainvillea family, Nyctaginaceae.

The tree has broad, thin leaves, smooth bark and bears clusters of green sweet-smelling flowers that mature into sticky barbed seeds.

Vegetative reproduction frequently results when fallen branches sprout or basal shoots develop into new trees.

The species often dominates mature coral cay vegetation, growing in dense, thick strands up to 20 m (66 ft) tall.

The natural vegetation was destroyed in order to scrape the guano and the island's landscape became barren.