'Oha Wai (Clermontia samuelii)
|Listed||September 3, 1999|
|Description||A tropical shrub.|
|Habitat||Humid tropical forest.|
|Threats||Habitat destruction and degradation caused by introduced mammalian herbivores and invasive plants.|
The 'oha wai is a shrub growing as tall as 16 ft (5 m). Its leaves are elliptical in shape, with blades 2-4 in (5-10 cm) long and 0.7-1.8 in (1.8-4.5 cm) wide. The upper surfaces of the leaves are dark green, often tinged purplish, and may be sparsely hairy. The lower surfaces are pale green and sparsely to densely hairy. The leaf margins are thickened, with shallow, ascending, rounded teeth. The tip and base of the leaves are typically sharply pointed. The inflorescences (or flowering clusters) bear two to five flowers on a peduncle (supporting stem) that is 0.2-0.7 in (4-18 mm) long. The hypanthium (a cup-like structure at the base of the flower) is widest on the top, 0.3-0.6 in (8-14 mm) long, and 0.2-0.4 in (5-10 mm) wide. The sepals and petals are both colored rose or greenish white to white, and are curved and tubular. The flowers are 1.4-2.2 in (36-55 mm) long and 0.2-0.4 in (5-10 mm) wide. The lobes of the sepals and petals are erect, and extend 0.2-0.5 times beyond the tube. Berries of this species have not yet been observed. The subspecies hanaensis is differentiated from samuelii by its greenish white to white flowers, longer narrower leaves with the broadest point near the base, and fewer hairs on the lower surface of the leaves.
The 'oha wai occurs in montane wet forest dominated by the ohi'a (Metrosideros polymorpha ), with with an understory of hapu u' (Cibotium sp.) and other native shrubs. The subspecies hanaensis is found at or below an elevation of 3,000 ft (915 m), while samuelii occurs between 6,000 and 6,900 feet (1,800 and 2,100 m).
The 'oha wai is a locally evolved (or endemic) species that has been reported from eight locations in East Maui, from Keanae Valley on the windward (northeastern) side to Manawainui on the more leeward (southeastern) side of Haleakala. The Hawaiian archipelago has an extremely large fraction of endemic species; about 89% of the indigenous flowering plants occur nowhere else in the world.
Threats to hanaensis include habitat destruction or degradation caused by introduced feral pigs (Sus scrofa ) and by competition and habitat change associated with non-native plants, such as glorybush (Tibouchina herbacea ) and two species of ginger (Hedychium spp.). The extremely invasive plants velvet tree (Miconia calvescens ) and Koster's curse (Clidemia hirta ) are also a potential threat. The subspecies samuelii is also threatened by wild pigs and invasive plants. The 'oha wai is known from several populations on the northeastern side of Haleakala, totaling fewer than 300 individuals. The populations occur on state owned land, within a Natural Area Reserve and a Forest Reserve. The subspecies hanaensis is known from several populations on the northeastern side of Haleakala, totaling fewer than 300 individuals. The populations occur on state owned land, within a Natural Area Reserve and a Forest Reserve. The subspecies samuelii is known from 5 to 10 populations totaling 50 to 100 individuals, most of which occur on the back walls of Kipahulu Valley, within Haleakala National Park, with two or three others on adjacent state owned land.
Conservation and Recovery
The population of samuelii in Haleakala National Park has been enclosed in a fence, and pigs have been eradicated there. The populations occurring on State Forest Reserve or State Natural Area Reserve lands are also being managed to conserve their indigenous ecological values, although pigs have not been eradicated. Actions needed to conserve the 'oha wai include the protection of its known critical habitats, and research into its biology and the deleterious effects of introduced mammalian herbivores and invasive plants, and ways of controlling those biological damages.
U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
Eastside Federal Complex
911 N. E. 11th Ave.
Portland, Oregon 97232-4181
U. S. Fish and Wildlife Service
Pacific Islands Ecoregion, Pacific Islands Fish and Wildlife Office
300 Ala Moana Boulevard, Room 3-122
P. O. Box 50088
Honolulu, Hawaii 96850
Telephone: (808) 541-3441
Fax: (808) 541-3470
U. S. Fish and Wildlife Service. 3 September 1999. "Endangered and Threatened Wildlife and Plants: Final Endangered Status for 10 Plant Taxa From Maui Nui, Hawaii." Federal Register 64 (171): 48307-48324.