Hibiscadelphus woodii (Wood's hau kuahiwi) was a species of flowering plant in the mallow family, Malvaceae, endemic to Kauai, Hawaii. It was a small tree, reaching a height of 2.5–5 m (8.2–16.4 ft). It was discovered in 1991 and described as a new species in 1995. Only four individuals were found at that time; three of those were crushed by a boulder and died between 1995 and 1998, and the last was found dead in 2011. Pollen was found to be inviable, no fruit set was ever observed and all attempts at propagation, including by cross-pollination with H. distans, failed.