Haplostachys haplostachya is a rare species of flowering plant in the mint family known by the common name honohono. It is endemic to Hawaii, where it is now limited to the island of Hawaii and has been extirpated from Kauai and Maui. It has been on the United States' endangered species list since 1979. Though there are few wild specimens left, the honohono is cultivated and kept as a garden plant in Hawaii.