Hibiscadelphus hualalaiensis (Hualalai hau kuahiwi) is a species of flowering plant in the mallow family Malvaceae that is endemic to the Big Island of Hawaii.
H. hualalaiensis is a small tree, reaching a height of and trunk diameter of .
It inhabits dry and mixed mesic forests on the slopes of HualÃÂlai at elevations of . Associated plants include à Âhia lehua (Metrosideros polymorpha), lama (Diospyros sandwicensis), mÃÂmane (Sophora chrysophylla), naio (Myoporum sandwicense), ÃÂlaa (Planchonella sandwicensis), pÃÂpala (Charpentiera spp.), aiea (Nothocestrum spp.), poolà(Claoxylon sandwicense), and Kikuyu grass (Pennisetum clandestinum).
The last known plant died in 1992, making it most likely extinct in the wild; any remaining plants are threatened by habitat loss. However, individuals have been breed in captivity and replanted in nature reserves of the Big Island.