CPC Plant Profile: Wood's Hau Kuahiwi
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Plant Profile

Wood's Hau Kuahiwi (Hibiscadelphus woodii)

Closeup of leaves and flower. Photo Credit: S. Perlman
Description
  • Global Rank: G1 - Critically Imperiled
  • Legal Status: Federally Endangered
  • Family: Malvaceae
  • State: HI
  • Nature Serve ID: 150244
  • Date Inducted in National Collection: 07/09/1992

There are seven known species of Hibiscadelphus, an genus endemic to Hawaii, five of which are now extinct in the wild. The recently discovered (Lorence 1995) H. woodii is one of the two Hibiscadelphus species with remaining wild populations. Unfortunately, this species appears to be heading for the same fate as other members of its genus. Within one year, the size of the one wild population declined from four (USFWS 2000) to two individuals (USFWS 2001). To make matters worse, the species doesnt appear to be producing fruit. Flowering material has been collected in March, April, and September, but no fruit set has been observed in spite of efforts to manually pollinate and bag the flowers. H. woodii, a member of the hibiscus family (Malvaceae) is a small, branched 2.5 to 5 meters tree with a rounded crown. The leaves have stalks 2.8 to 5.8 centimeters long with star-shaped hairs when young, which are lost when the leaves mature. Flowers are borne on individual stalks 1.4 to 2.1 centimeters with star shaped hairs. Below each flower are 4 to 6 bracts 11 to 15 millimeters long and 1.8 to 4 millimeters wide. The corolla is 4.5 to 4.7 centimeters long, yellow with a coppery tinge when fresh, which rapidly turns purplish-maroon. (USFWS 1998).

Participating Institutions
Updates
Nature Serve Biotics
  • 05/02/2017

Recorded from only a single location in Kalalau Valley, Kauai. This species was discovered in 1991, when a population of 4 trees was found. No additional plants have been located since then. No fruit set has yet been observed on the plants. The habitat of this species is being degraded by the presence of feral goats and pigs. The invasion of alien plants represents an additional threat.

  • 01/01/2010

Threats to H. woodii include: habitat degradation by feral goats and pigs competition from the invasive introduced plant species Erigeron karvinskianus (daisy fleabane) nectar robbing by an introduced bird, the Japanese white-eye (Zosterops japonicu

  • 01/01/2010

Number of Populations: 1 (USFWS 2001) Number of Plants: 2 (USFWS 2001)

  • 01/01/2010

The Lyon Arboretum has successfully propagated H. woodii by tissue culture (USFWS 1998).

  • 01/01/2010

There have been numerous attempts by NTBG to propagate H. woodii such as grafts, cuttings air layers, tissue culturing, and efforts to manually outcross and bag the flowers yet none of those attempts have proved successful. No viable seed has yet been collected (Wood et al. 2002)

  • 01/01/2010

1. Research on breeding biology is needed to ensure seed production. 2. Construct exclosures around two remaining trees along the stream in Limahuli Valley and the back of Hanakapiai Valley. Once the exclosures are constructed, the area should be managed by removing weeds such as Rubus rosifolius (thimbleberry), Clidemia hirta (Kosters curse), and Lantana camara (lantana). Without enclosures, the population of H. woodii will continue to decline due to habitat degradation by feral pigs. 3. Conduct and encourage research to reduce the impacts of the Japanese white-eye. 4. Hunting to reduce feral ungulates and subsequent control of alien plant species. After the numbers of feral ungulates are reduced, alien plant control should be initiated. 5. Begin attempts to outplant H. woodii in protected areas. 6. Conduct pollination biology and seed dispersal studies. Recommendations derived from M.H. Chapin, M. Maunder, and USFWS (1998, 2000).

  • 01/01/2010

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

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Photos
Nomenclature
Taxon Hibiscadelphus woodii
Authority Lorence and W.L. Wagner
Family Malvaceae
CPC Number 15806
ITIS 507890
USDA HIWO
Common Names hau kuahiwi
Associated Scientific Names Hibiscadelphus woodii
Distribution H. woodii is endemic to Kauai and has been found only at the site of its original discovery on State owned land in Kalalau Valley, within the Na Pali Coast State Park. (USFWS 1998).
State Rank
State State Rank
Hawaii S1
Habitat

H. woodii is found at elevations approximately 915 meters (3,000 ft) on basalt talus or cliff walls in Metrosideros polymorpha (ohia) montane mesic forest (USFWS 2000). Associated species of H. woodii include Bidens sandwicensis (kookoolau), Artemisia australis (no common name [NCN]), Melicope pallida (alani), Dubautia sp. (naenae), Lepidium serra (anaunau), Lipochaeta sp. (nehe), Lysimachia glutinosa (kolokolo kuahiwi), Carex meyenii (NCN), Chamaesyce sp. (akoko), Hedyotis sp. (manono), Nototrichium sp. (kului), Panicum lineale (NCN), Myrsine sp. (kolea), and the federally endangered species Stenogyne campanulata (NCN), Lobelia niihauensis (NCN), and Poa mannii (Manns bluegrass).

Ecological Relationships

Unknown.

Pollinators
Common Name Name in Text Association Type Source InteractionID

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