Hawaiian hibiscus

Hawaiian Hibiscus
Missing image Maohauhele.jpg The ma‘o hau hele is the state flower of Hawai‘i
Scientific classification
Kingdom: Plantae Division: Magnoliophyta Class: Magnoliopsida Order: Malvales Family: Malvaceae Genus: Hibiscus
Species
See text

The genus Hibiscus includes some 200 species, seven of which are regarded as native Hawaiian hibiscus. Although tourists regularly do associate the hibiscus flower with their experiences visiting the US state of Hawai‘i, and the plant family Malvaceae includes a relatively large number of species that are native to the Hawaiian Islands, those flowers presented to or regularly observed by tourists are generally not the native hibiscus flowers. Most commonly grown as ornamental plants in the Islands are the Chinese hibiscus (Hibiscus rosa-sinensis) and its numerous hybrids.

The native plants in the genus Hibiscus in Hawai‘i are thought to have derived from four independent colonization events: two for the five endemic species (four closely related species plus the yellow-flowered species) and one each for the two indigenous species (Wagner, Herbst, and Sohmer, 1990).

The native hibiscus (Genus Hibiscus) found in Hawai‘i are:

• Hibiscus arnottianus A. Gray – koki‘o is an endemic species of hibiscus with white flowers. Three subspecies are recognized: H. arnottianus arnottianus found in the Wai‘anae mountain of western O‘ahu; H. a. immaculatus which is very rare (listed as endangered) on Moloka‘i; and H. a. punaluuensis from the Ko‘olau mountain on O‘ahu. Perhaps only a dozen plants of H. a. immaculatus exist in nature. This species is closely related to H. waimeae. Sometimes planted as an ornamental.
• Hibiscus brackenridgei A. Gray – ma‘o hau hele is a tall shrub with bright yellow flowers, closely related to the widespread H. divaricatus. Two subspecies are recognized: H. b. brackenridgei, a sprawling shrub to an erect tree found on Moloka‘i, Lana‘i, Maui, and Hawai‘i; and H. b. mokuleianus, a tree from dry habitats on Kaua‘i and Wai‘anae mountain on O‘ahu. This species is listed as an endangered species by the USFWS. The yellow flower of this species is the official state flower of Hawai‘i, and although endangered in its natural habitats, has become a moderately popular ornamental in Hawaiian yards.
• Hibiscus clayi Degener & Degener – An endemic shrub or small tree with bright red flowers, generally similar to H. kokio, and found in nature on Kaua‘i in dry forests. Listed as endangered by USFWS.

• Hibiscus furcellatus Desr. – a pink-flowered hibiscus considered an indigenous species, typically found in low and marshy areas of the West Indies, Florida, Central and South America, and Hawai‘i. It is known to the Hawaiians as ‘akiohala, ‘akiahala, hau hele, and hau hele wai.
• Hibiscus kokio Hillebr. – koki‘o or koki‘o ‘ula is a shrub or small tree with red to orangish (or rarely yellow) flowers. This endemic species is not officially listed, but considered rare in nature. Two subspecies are recognized: H. kokio kokio found in dry to wet forests on Kaua‘i, O‘ahu, Maui, and possibly Hawai‘i; and H. k. saintjohnianus from northwestern Kaua‘i.
• 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 Hawai‘i, but may have been introduced by the early Polynesians.
• Hibiscus waimeae A. Heller – koki‘o ke‘oke‘o or koki‘o kea is a Hawaiian endemic, gray-barked tree, 6-10 m tall, with white flowers that fade to pink in the afternoon. Two subspecies are recognized: H. waimeae hannerae (rare and listed as endangered) found in northwestern valleys of Kaua‘i, and H. w. waimeae occurring in the Waimea Canyon and some western to southern valleys on Kaua‘i. This species closely resembles H. arnottianus in a number of characteristics.

Other Malvaceae

In addition to the species of Hibiscus listed above, there are several other related Hawaiian plants of the family Malvaceae whose flowers resemble hibiscus flowers, although are generally smaller. The endemic genus, Hibiscadelphus, comprises six species described from Hawai‘i. Three of these are now thought to be extinct and the remaining three are listed as endangered. Another endemic genus, Kokia, comprises four species of trees. All but one (K. kauaiensis) are listed and either extinct or nearly extinct in the wild.

Three endemic species of the New World genus, Abutilon occur in Hawai‘i: A. eremitopetalum, A. menziesii, and A. sandwicense; all are listed as endangered. The cotton plant (genus Gossypium), whose bright yellow flowers are certainly hibiscus-like, includes one endemic: G. tomentosum, uncommon but found in dry places on all the main islands except Hawai‘i. The widespread milo (Thespesia populnea) is an indigenous tree with yellow and maroon flowers.

Reference

• Wagner, W. L., Derral R. Herbst, and S. H. Sohmer (1990). Manual of the Flowering Plants of Hawai‘i, Vol. I. University of Hawaii Press, Honolulu. 988 pp.