Koki'o Ke'oke'o

Hibiscus waimeae ssp. hannerae

Description

Hibiscus waimeae ssp. hannerae, or koki'o ke'oke'o, a gray-barked tree of the mallow family that reaches a height of 20-33 ft (6.1-10 m), has star-shaped hairs densely covering its leaf and flower stalks and branchlets. The circular to broadly egg-shaped leaves are usually 2-7 in (5-17.8 cm) long and 1.2-5 in (3-12.7 cm) wide. The strongly fragrant flowers are borne singly near the ends of the branches on flower stalks 0.8-1.2 in (2-3 cm) long. The calyx is tubular, normally 1.2-1.8 in (3-4.6 cm) long, with lobes 0.2-0.6 in (0.5-1.5 cm) long. The flaring petals are white when the flower opens in the morning, but fade to pinkish in the afternoon. The petals, usually 1.6-2.4 in (4-6 cm) long, are basally attached to the staminal column to form a tube about 0.6 in (1.5 cm) long. The exserted staminal column is up to 6 in (15.2 cm) long and reddish to crimson at the tip. The filaments arise in the upper half of the staminal column and spread up to 1 in (2.5 cm) long. The fruit is a cartilaginous, egg-shaped capsule 0.7-1 in (1.8-2.5 cm) long and hairless. Two subspecies are recognized, both occurring on Kauai: ssp. hannerae and ssp. waimeae. Subspecies hannerae is distinguished by having larger leaves but smaller flowers. The species is distinguished from others of the genus by the position of the anthers along the staminal column, length of the staminal column relative to the petals, color of the petals, and length of the calyx.

Habitat

H. waimeae ssp. hannerae is growing in Limahuli Valley in an 'ohi'a-uluhe lowland wet forest at elevations between 620 and 1,850 ft (189 and 564 m). Associated species at this location include 'ahakea, 'ama'u, haha, ha'iwale, and Syzygium sp. The Hanakapiai Valley population is growing at elevations between 720 and 1,200 ft (219.5 and 365.7 m) in Pisonia sp. (papala kepau)— Charpentiera elliptica (papala) lowland mesic forest with 'ahakea, hame, kopiko, mamaki, and the alien species Aleurites moluccana (kukui).

Distribution

Three collections of H. waimeae ssp. hannerae are known, all from the island of Kauai. The Kalihiwai population of this subspecies is apparently extinct, and the two remaining populations of about 75-125 total individuals are found in adjacent valleys on Kauai's northern coast on state and private land. Between 50 and 100 plants are scattered over a 1,100 sq ft (102 sq m) area along the stream in Limahuli Valley, while another 50 or so plants were distributed over a 110-1,100-sq ft (10-102-sq m) area below the cliffs in the back of Hanakapiai Valley before Hurricane 'Iniki. After the hurricane, only 25 plants remain in Hanakapiai Valley.

Threats

The major threats to H. waimeae ssp. hannerae are habitat degradation by feral pigs; competition with alien plant species, including thimbleberry, Koster's curse, and lantana; and a risk of extinction from naturally occurring events and reduced reproductive vigor due to the small number of remaining populations.

All known populations of H. waimeae ssp. hannerae are threatened by feral pigs. Hurricane Iniki destroyed half of one population, and future hurricanes are always a threat.

Conservation and Recovery

Since Hurricane Iniki in 1992, the National Tropical Botanical Garden has propagated 13 plants from cuttings collected from upper Limahuli Preserve in June and July of 1997. These plants will be out-planted in Limahuli Preserve in the near future.

A total of 27 H. waimeae ssp. hannerae plants have been successfully cultivated through 1997 on the grounds of the National Tropical Botanical Garden and Waimea Arboretum.

The two remaining populations along the stream in Limahuli Valley and the back of Hanakapiai Valley need to be enclosed. Without this protection, this species will continue to decline due to degradation of habitat by feral pigs. Once enclosed, those areas should undergo management to remove alien plant species like thimbleberry, Koster's curse, and lantana.

Because of the success in cultivating additional plants on the grounds of the National Tropical Botanical Garden and Waimea Arboretum, attempts to outplant should occur in areas that have been protected and are under management to control alien plant species.

Contact

U.S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
Eastside Federal Complex
911 N.E. 11th Ave.
Portland, Oregon 97232-4181
(503) 231-6121
http://pacific.fws.gov/

Reference

U.S. Fish and Wildlife Service. 1988. "Kauai II: Addendum to the Recovery Plan for the Kauai Plant Cluster." U.S. Fish and Wildlife Service, Portland, Oregon. 84+ pp.