'Ohe'ohe

Tetraplasandra gymnocarpa

Description

'Ohe'ohe (Tetraplasandra gymnocarpa ) is a tree in the ginseng family. It is either hairless or with fuzzy and short-lived hairs on the young leaves and flower clusters, and grows to a height of 8-33 ft (2.4-10 m). The leaves, 12-22 in (30.5-56 cm) long, have 7-21 leathery, oval to elliptic leaflets per leaf. Each leaflet, 2.8-7.1 in (7.1-18 cm) long and 1.2-3.1 in (3-7.9 cm) wide, is folded upward along the midveins. The flowers are usually arranged in threes or in an umbrella-shaped arrangement. Petals are 0.2-0.3 in (0.5-0.8 cm) long and usually number five to six per flower, with an equal number of stamens. The ovary, which usually has three to four sections, is atop the receptacle (base of the flower) in a superior position, due to the expansion of the ovary disk (outgrowth of the receptacle) and the reduction of the hypanthium (basal portion of the flower). Fruits are purplish, oval or top-shaded drupes, 0.2-0.5 in (0.5-1.3 cm) long, that enclose a papery endocarp and single seed. This species was observed in flower and fruit in November 1991 and in fruit in May and September 1991.

T. gymnocarpa is distinguished from all other species in the genus in that its ovary appears fully superior.

Habitat

T. gymnocarpa is typically found on windswept summit ridges or in gullies in wet or sometimes mesic forests between elevations of 820-2,790 ft (250-850.4 m). Associated plants include 'ohi'a (Metrosideros collina ), olapa, uluhe (Dicranopteris linearis ), kopiko (Psychotria spp.), kamakahala (Labordia spp.) and kolea.

Distribution

T. gymnocarpa was historically known from Punahuu, Waikakalaua Gulch, Mount Olympus, and the region between Niu and Wailupe, all in the Koolau Mountains of Oahu.

Seventeen populations are now scattered along summit ridges of the Koolau Mountains over a distance of 28 mi (45 km); from the region of Paumalu at the northern extreme to Kuliouou and Waimanalo at the southeasternmost point. One population in the Waianae Mountains, located on Palikea Ridge on the border of federal and private land, was last visited in 1954, and it is not known if it still exists. Most populations contained between one and six individuals in 1997, although the total for all occur-rences was estimated at fewer than 200 plants.

Threats

The primary threats to T. gymnocarpa are competition with the aggressive exotic Koster's curse (Clidemia hirta ), habitat destruction by feral pigs, and reduced reproductive vigor due to the limited gene pool.

Conservation and Recovery

The National Tropical Botanical Garden has attempted propagation of T. gymnocarpa seeds with no germination success. To prevent extinction of this species, propagation materials should be collected immediately from remaining populations.

Contacts

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

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

Reference

U.S. Fish and Wildlife Service. 28 March 1994. "Endangered and Threatened Wildlife and Plants; Determination of Endangered or Threatened Status for 11 Plants Species from the Koolau Mountain Range, Island of Oahu, HI." Federal Register 59 (59): 14482-14492.