Hibiscadelphus giffardianus viscosa"), and naio ("Myoporum sandwicense"). "H. giffardianus" is a small tree, reaching a height of and trunk diameter of . Hibiscadelphus giffardianus 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 ōhia lehua ("Metrosideros polymorpha"), koa ("Acacia koa"), mānele ("Sapindus saponaria"),
Hawaiian tropical rainforests milo ("Thespesia populnea") for the past 1,000–2,000 years. The Polynesian-introduced noni ("Morinda citrifolia"), pia ("Tacca leontopetaloides"), and kī ("Cordyline fruticosa") are also common in this zone. Other native species include pololei ("Ophioglossum concinnum"), ākia ("Wikstroemia" spp.), loulu fan palms ("Pritchardia" spp.), ōhia lehua ("Metrosideros polymorpha"), and lama ("Diospyros sandwicensis"). Mixed mesic forests, at on the windward slopes of the large islands in addition to the summit of Mount Lānaihale on Lānai, receive of rainfall annually and thus may not be true rainforests. The forest canopy, dominated by koa ("Acacia koa") and ōhia lehua ("Metrosideros polymorpha"), is somewhat open, but tree