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Plant Profile

Hualalai Hau Kuahiwi (Hibiscadelphus hualalaiensis)

Full view of the tree in-situ. Photo Credit: National Tropical Botanical Garden

Global Rank: GH - Possibly Extinct
Legal Status: Federally Endangered
Family: Malvaceae
State: HI
Nature Serve ID: 161685
Lifeform: Tree
Date Inducted in National Collection: 04/01/1990

Description:

There are seven species of Hibiscadelphus, an genus endemic to Hawaii, and four of those species are now extinct. H. hualalaiensis is one of the 3 remaining species, but is itself extinct in the wild, with only 22 plants surviving in cultivation today. The species was discovered in 1909 on the slopes of the volcano Hualalai on the big island of Hawaii, and was thus named after the volcano where it occurred. H. hualalaiensis, a member of the hibiscus family (Malvaceae) is a 5 to 7 meter tree that has a trunk up to 30 centimeters in diameter. The leaf blades are heart-shaped with entire margins. The flower petals are greenish yellow on the outside, and yellowish green fading to purplish within (2 to 5.5 cm. Long). The fruit of H. hualalaiensis is woody with dense hairs covering its seed (USFWS 1998).

Where is Hualalai Hau Kuahiwi (Hibiscadelphus hualalaiensis) located in the wild?

Habitat:

H. hualalaiensis is restricted to dry to mesic forests and lava flows, 915 to 1,020 meters elevation on Hawaii (Wagner et al. 1999).Associated species of H. hualalaiensis include Metrosideros polymorpha (ohia), Diospyros sandwicensis (lama), Sophora chrysophylla (mamane), Myoporum sandwixense (naio), Pouteria sandwicensis (alaa), Charpentiera sp. (papala), Nothocestrum sp. (aiea), Claoxylon sandwicense (poola), and Pennisetum clandestinum (kikuyu grass).

Distribution:

This species was historically known from three populations in the Puu Waawaa region of Hualalai, on the island of Hawaii. In 1992, the last known wild tree of H. hualalaiensis died, making this speci

States & Provinces:

Hualalai Hau Kuahiwi can be found in Hawaii

Which CPC Partners conserve Hualalai Hau Kuahiwi (Hibiscadelphus hualalaiensis)?

National Tropical Botanical Garden

Not Sponsored

Assigned 06/09/17

Harold L. Lyon Arboretum

Not Sponsored

Assigned 07/24/23

CPC's Plant Sponsorship Program provides long term stewardship of rare plants in our National Collection. We are so grateful for all our donors who have made the Plant Sponsorship Program so successful. We are in the process of acknowledging all our wonderful plant sponsorship donors on our website. This is a work in progress and will be updated regularly.

Conservation Actions

Nature Serve Biotics

05/02/2017

This species was discovered in 1909 in the district of North Kona on the island of Hawaii, when about a dozen trees were found. The last known wild tree died in the 1990's. Descendants of the wild trees remain in cultivation, and some have been outplanted within the former range of the species. The species' forest habitat has been grazed since the 1800's. Threats to the outplanted individuals include cattle, goats, pigs, fire, and alien plants.

01/01/2010

Threats to H. hualalaiensis include: fire degradation of habitat by domestic and feral cattle, feral pigs and sheep flower and seed predation by rats competition from invasive introduced plants such as Lantana camara (lantana) ranching activitie

01/01/2010

Number of Populations: 0 (USFWS 2001) Number of Plants: 22 (USFWS 2001)

01/01/2010

In the 1970's, a number of individuals studied the effects of hybridization between this species the closely related, also endangered, Hibiscadelphus giffardianus. (Baker & Allen 1976, Baker & Allen 1977, Carr & Baker 1977, Degener & Degener 1977) These two species did not naturally occur together, but had been planted near each other in Hawaii Volcanoes National Park during early conservation efforts. It was eventually determined that this situation resulted in hybridization between the two species. The decision was made to remove H. hualalaiensis from the park in order to maintain the genetic integrity of both species. Today, both of these species are maintained in cultivated settings.

01/01/2010

Small areas have been fenced around the two outplanted populations to exclude livestock and feral ungulates at the Puu Waawaa Wildlife Sanctuary and the Kokia Sanctuary in Kawaihae. No other specific measures have been taken. Volcano Rare Plant Facility (VRPF) has 10 plants in their nursery and Waimea Falls Park (WFP) has 4 plants; however they are doing poorly. The National Tropical Botanical Garden (NTBG) currently has ex situ holdings of 172 seeds in its seed bank, and 14 individuals in the botanical garden (USFWS 1998).

01/01/2010

1. Outplant new populations in areas managed. Prior to outplanting, the sites should be fenced, free of weeds and free of rats and feral ungulates. 2. Reduce threats from rodent predation. Diphacinone bait block are successfully being used but a more broad scale method such as aerial dispersal of rodenticide should be considered. 3. Protect populations from fire. Steps should be taken to prevent the extirpation of the outplanted populations and future outplanting from wildfires. Removing alien grasses may help to reduce the fuel load. 4. Conduct pollination biology, seed dispersal mechanism, and molecular phylogenetic studies on H. hualalaiensis. 5. Map genetic diversity in the surviving populations of H. hualalaiensis. 6. Test the influence of weeding and fencing on populations of H. hualalaiensis. Recommendations derived from M.H. Chapin, M. Maunder, and USFWS (1998).

01/01/2010

1. Establish secure ex situ stocks with full founder representation. 2. Develop proper horticultural protocols and pest management for H. hualalaiensis. 3. Survey ex situ holdings and conduct molecular fingerprinting. Recommendations derived from M.H. Chapin and M. Maunder.