'Oha Wai

Clermontia oblongifolia ssp. mauiensis

Description

The 'oha wai (Clermontia oblongifolia ssp. mauiensis ) is a shrub or tree in the bellflower family (Campanulaceae) that grows to heights of 6.6-23 ft (2-7m). The leaves are located on petioles and are 1-4.5 in (2.5-11.5 cm) long. These oblong or elliptic leaves have thickened, rounded teeth and reach a length of 3-7.5 in (7.6-19 cm). This plant produces two or three flowers that are bunched together on a 0.2-1.8 in (0.5-4.5 cm) long stalk. The flower itself is 2.4-3.1 in (6-7.9 cm) long. The calyx and corolla are similar in size and appearance in that each forms an arched tube which is greenish white or purplish on the outside and white or cream-colored on the inside. The orange-colored fruit is a spherical berry. This sub-species is distinguished from other C. oblongifolia by its leaf shape; the lengths of its leaves, the leaf stalk, and flower stalk; the shapes of the leaf tip and the flower bud; and the purple or magenta color of the fused stamens.

Habitat

C. oblongifolia ssp. mauiensis typically grows on the sides of ridges in 'ohi'a dominated wet forests at an elevation of 2,800-3,000 ft (853-914 m). These wet, montane communities usually occur on steep windward slopes and valley walls. They are often characterized by bogs with thick peat overlaying an impervious clay substrate in which grow hum-mocks of sedges, grasses, stunted trees, and shrubs. Associated native species include Coprosma, Clermontia, Hedyotis, and Melicope.

Distribution

C. oblongifolia ssp. mauiensis was known historically from Lanai and Maui. The subspecies mauiensis was first collected on Lanai in Mahana valley and Kaiholena Valley. No specimens of the plant have been found on Lanai since 1913. C. oblongifolia was collected from East Maui on the windward slopes of Mt. Haleakala along the Kailua ditch trail in the valley of Honomanu at an elevation of 2,800-3,000 ft (853-914 m) in the rainforest. It was found growing in the company of C. macrocarpa, C. kakeana, the most common species in that locality, and C. arborescens. The last collection of this species on East Maui was made in 1927. On West Maui, the ssp. mauiensis was collected for the first time in the 1980s. This single individual exists along the trail to Puukukui in the Honokowai section of the West Maui Natural Area Reserve on state land.

In May 1994, Richard Palmer of the University of Hawaii at Manoa collected material possibly referable to C. oblongifolia ssp. mauiensis at 3,100 ft (945 m) elevation on the lower flume road in Koolau Forest Reserve, northwest Haleakala. Two individuals were observed on jeep road cuts, with C. arborescens and C. kakeana growing nearby. DNA analysis of these specimens and material from the West Maui C. oblonglfolia ssp. mauiensis indicates that C. oblongifolia and its subspecies may be hybrids of C. arborescens and C. kakeana. This information has not been confirmed as of the writing of this article. The genus Clermontia comprises 22 species, all restricted to the Hawaiian Islands. The specific epithet oblongifolia refers to the oblong shape of the leaf blade, while the subspecies epithet mauiensis refers to Maui Island, one of its places of occurrence.

In summary, C. oblongifolia ssp. mauiensis is currently known to exist only on West Maui. Good quality habitat still exists for this species in the windward rainforests of East Maui, and this taxon may still occur there. Because of the degradation of forest in its former habitat on Lanai, this taxon is likely extirpated on that island.

Threats

Many of the native plants of Maui are very vulnerable to habitat degradation caused by the browsing, rooting, and trampling of goats, pigs, sheep, and cattle. These native species are also threatened by competition in their habitats for space, light, water, and nutrients from naturalized alien species; human-ignited fires; recreational activities by tourists and visitors; and military exercises. Any of these threats could extirpate the single remaining C. oblongifolia plant, although it is not currently threatened by pig rooting. The complete lack of genetic diversity that exists for this species also means that its reproductive vigor is likely impaired.

Conservation and Recovery

Over the past three years, Maui Land and Pine and the Nature Conservancy of Hawaii have conducted management for the reduction of pigs in Kapunakea Preserve and the Honokowai section of the West Maui Natural Area Reserve where this sub-species still occurs. The combination of fencing, snaring and hunting under this program has reduced pigs to the point where they are no longer a direct threat to the single known individual of C. oblongifolia ssp. mauiensis, so localized fencing for this individual is no longer necessary.

Germ plasm from C. oblongifolia ssp. mauiensis is not held in any cultivated collection. Fruits from the East Maui plants were collected, then provided to the Lyon Arboretum. Attempts by Lyon Arboretum to propagate C. oblongifolia ssp. mauiensis were unsuccessful.

Contacts

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

Pacific Joint Venture
300 Ala Moana Blvd., Rm 3-122
Honolulu, Hawaii 96850-0056
Telephone: (808) 541-2749
Fax: (808) 541-2756

Reference

U.S. Fish and Wildlife Service. 15 May 1992. "Endangered and Threatened Wildlife and Plants; Determination of Endangered or Threatened Status for 15 Plants from the Island of Maui, Hawaii." Federal Register 57 (95): 20772-20787.