A study of the species of Leucaena Bth. and their hybrids as cultivated in Netherlands New Guinea, revealed that the systematical status of Leucaena insularum (Guill.) Dan. needed to be re-examined. L. insularum was first described by Guillemin in 1837 and based on a specimen from Tahiti. He named it Acacia insularum Guill. In 1932, Daniker placed A. insularum in Leucaena and published the combination Leucaena insularum (Guill.) Dan. Bentham had already placed the same species in Leucaena in 1846 and then named it Leucaena forsteri Bth. It appeared that some specimens kept in the Leiden Herbarium, collected in New Guinea, the Solomon Islands, and the Moluccas, which had been identified as Leucaena sp., belonged to a taxon that was either identical with, or closely allied to, Leucaena insularum (Guill.) Dan. Dr. R. D. Hoogland (C.S.I.R.O. Herbarium, Canberra) supplied information which led to the identification of the specimens as Piptadenia novo-guineensis Warburg. Warburg’s detailed description made it possible to identify the specimens with certainty.