Hibiscadelphus crucibracteatus

Hibiscadelphus crucibracteatus, called lava hau kuahiwi in Hawaiian, is an extinct species of flowering plant in the mallow family, Malvaceae, that was endemic to the island of Lānaʻi in Hawaii. It is known from a single tree, found by Peter Connally on the Puhielelu ridge in 1981 and described in 1984 by the botanist Robert W. Hobdy. The tree reached about six metres with a rounded crown and smooth gray bark, with papery heart-shaped leaves seven to ten centimetres long and flowers borne singly on short stalks. It grew in a remnant pocket of moist native forest on an eroded ridge on the windward slopes of Lānaʻi, beside native trees such as kauila and ʻōhiʻa ha. Its closest relatives are Hibiscadelphus wilderianus and Hibiscadelphus giffardianus, from which it differs mainly in its bracts, capsules and petals. The only known tree died within a few years, damaged by introduced chital deer despite being fenced, and seed collected on several occasions never germinated. The IUCN lists it as Extinct, while NatureServe treats it as possibly extinct.