Hibiscus arnottianus A.Gray - kokio keokeo is an endemic species of hibiscus with white flowers. Three subspecies are recognized: H. arnottianus ssp. arnottianus found in the Waianae Range of western Oahu; H. a. ssp. immaculatus which is very rare on Molokai; and H. a. ssp. punaluuensis from the Koolau Range on Oahu. Perhaps only a dozen plants of H. a. ssp. immaculatus exist in nature in mesic and wet forests. This species is closely related to H. waimeae, and the two are among the very few members of the genus with fragrant flowers. It is sometimes planted as an ornamental or crossed with H. rosa-sinensis. In the Hawaiian language, the white hibiscus is known as the pua aloalo.
Hibiscus brackenridgei A.Gray - mao hau hele is a tall shrub with bright yellow flowers, closely related to the widespread H. divaricatus. Two subspecies are recognized: H. b. ssp. brackenridgei, a sprawling shrub to an erect tree found in dry forests and low shrublands at elevations of above sea level on Molokai, Lanai, Maui, and the island of Hawaii; and H. b. ssp. mokuleianus, a tree from dry habitats on Kauai and the Waianae Range on Oahu. This species is listed as an endangered species by the USFWS. The yellow flower of this species was made the official state flower of Hawaii on 6 June 1988, and although endangered in its natural habitats, has become a moderately popular ornamental in Hawaiian yards.
Hibiscus clayi O.Deg. & I.Deg. is an endemic shrub or small tree with bright red flowers, generally similar to H. kokio, and found in nature on Kauai in dry forests. It is listed as endangered by USFWS.
Hibiscus furcellatus Desr. is a pink-flowered hibiscus considered an indigenous species, typically found in low and marshy areas of the Caribbean, Florida, Central and South America, and Hawaii, where it is known as akiohala, akiahala, hau hele, and hau hele wai.
Hibiscus kokio Hillebr., kokio or kokio ula is a shrub or small tree with red to orangish flowers. This endemic species is not officially listed, but considered rare in nature. Two subspecies are recognized: H. kokio ssp. kokio found in dry to wet forests on Kauai, Oahu, Maui, and possibly Hawaii at elevations of ; and H. k. ssp. saintjohnianus from northwestern Kauai at elevations of.
Hibiscus tiliaceus L., hau, is a spreading shrub or tree common to the tropics and subtropics, especially in coastal areas. This species is possibly indigenous to Hawaii, but may have been introduced by the early Polynesians.
Hibiscus waimeae A.Heller, kokio keokeo or kokio kea, is a Hawaiian endemic, gray-barked tree, tall, with white flowers that fade to pink in the afternoon. Two subspecies are recognized: H. waimeae ssp. hannerae found in northwestern valleys of Kauai, and H. w. ssp. waimeae occurring in the Waimea Canyon and some western to southern valleys on Kauai. This species closely resembles H. arnottianus in a number of characteristics.
In addition to the species of Hibiscus listed above, flowers of several other related Hawaiian plants of the family Malvaceae resemble Hibiscus flowers, although are generally smaller. The endemic genus, Hibiscadelphus, comprises seven species described from Hawaii. Three of these are now thought to be extinct and the remaining four are listed as critically endangered or extinct in the wild. Another endemic genus, Kokia, comprises four species of trees. All but one are listed as either extinct or nearly extinct in the wild. Three endemic species of the pantropical genus, Abutilon occur in Hawaii: A. eremitopetalum, A. menziesii, and A. sandwicense; all are listed as endangered. Cotton plants, whose bright yellow flowers are certainly hibiscus-like, include one endemic: G. tomentosum, uncommon but found in dry places on all the main islands except Hawaii. The widespread milo is an indigenous tree with yellow and maroon flowers. South Korea's national flower is the Hibiscus syriacus which is widely found in Hawaii, too.
