Rock discovered a single tree at Kīpuka Puaulu, now part of Hawaii Volcanoes National Park. This tree died in 1930, but cuttings were saved. Several hundred individuals have since been planted in the park, but no natural regeneration has been observed and few trees produce viable seeds. Hibiscadelphus hualalaiensis - This species formerly occurred in North Kona. The last wild tree died in 1992, but it survives in cultivation and trees have been outplanted in forest reserves. Hibiscadelphus stellatus - recently described species. 99 wild individuals are known to occur in Kaua`ula valley in Western Maui. †Hibiscadelphus wilderianus - Possibly extinct around 1912. Only known from a single tree which was discovered at Auwahi on Maui. Hibiscadelphus woodii - This species was discovered in 1991, on Kauai. 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. However, one individual was found on a cliffside in Kalalau Valley in January 2019, and a month later two more were found. Hibiscadelphus x puakuahiwi - A hybrid between H. giffardianus and H. hualalaiensis. In the 1960s both species were planted on Mauna Loa in Hawaii Volcanoes National Park, where only the former occurred naturally. The two cross-pollinated, and the hybrid seeds were unknowingly collected and planted. When discovered in 1973 the hybrids and H. hualalaiensis trees were cut down, although at least one hybrid remains as of 2011. References Wagner, Warren L.; Herbst, Darral R.; Sohmer, S. H., Manual of the Flowering Plants of Hawai'i. University of Hawai'i Press, 1999 External links A tree's tribulations Hibiscus articles The plant genus Hibiscadelphus in Hawaii Endemic flora of Hawaii Malvaceae genera