The large leaves are opposite or ternate, glabrous, and glossy, entire (simple with smooth margins), and obtuse to rounded at apex.

The very sticky fruits, in which small birds are often trapped, are narrowly ellipsoidal, and 2–3 centimetres (0.79–1.18 in) long, having five ribs.

In the Seychelles, the sticky seeds of a related species, Pisonia grandis, regularly causes seabird deaths, and research suggests that the seeds evolved to be transferred on the plumage of seabirds to distant islands, enabling the long-distance dispersal of the species.

The plant is almost extinct in the North Island, partly because the large leaves of P. brunoniana are eagerly eaten by browsing animals such as possums, goats and feral cattle.

Two variegated cultivars are sold as P. brunoniana in New Zealand nurseries, although one of these, which has leaves extensively marbled with white, may in fact be P. umbellifera, a similar species which occurs throughout the tropical Indo-Pacific.