Hydnocarpus is a genus of medium to large trees in the Family Achariaceae; the genus was previously placed in the now defunct family Flacourtiaceae. Species have been recorded from Indochina, Indonesia, Malaysia and the Philippines.

The Flacourtiaceae is a defunct family of flowering plants whose former members have been scattered to various families, mostly to the Achariaceae and Salicaceae. It was so vaguely defined that hardly anything seemed out of place there and it became a dumping ground for odd and anomalous genera, gradually making the family even more heterogeneous. In 1975, Hermann Sleumer noted that "Flacourtiaceae as a family is a fiction; only the tribes are homogeneous."