Hibiscadelphus giffardianus (Kilauea hau kuahiwi) is a species of flowering plant in the mallow family, Malvaceae, that is endemic to the Big Island of Hawaii. It is believed to be extinct in the wild; any remaining plants are threatened by habitat loss. Cultivated plants exist in Hawaii Volcanoes National Park. It inhabits mixed mesic forests on the slopes of Mauna Loa at elevations of . Associated plants include ʻōhiʻa lehua (Metrosideros polymorpha), koa (Acacia koa), mānele (Sapindus saponaria), hoio (Diplazium sandwicianum), pilo (Coprosma spp.), māmaki (Pipturus albidus), kōpiko (Psychotria spp.), olopua (Nestegis sandwicensis), alani (Melicope spp.), ʻaʻaliʻi (Dodonaea viscosa), and naio (Myoporum sandwicense). H. giffardianus is a small tree, reaching a height of and trunk diameter of .