Alani

Melicope ovalis

Description

Melicope ovalis is a tree of the citrus family (Rutaceae) that can reach 16 ft (5 m) in height; its new growth has fine, short, and brownish hairs, then soon becomes hairless. The opposite, leathery, and broadly elliptic leaves are 3.1-6.3 in (8-16 cm) long, 1.6-3.9 in (4-10 cm) wide, and have petioles 1.2-1.6 in (3-4 cm) long. The upper and lower surfaces of the leaves are hairless, and bruised foliage has an anise odor similar to that of M. anisata (mokihana). Each flower cluster is on a main stalk 0.1-0.5 in (2.5-13 mm) long and comprises three to seven flowers on individual stalks 0.4-0.5 in (10-13 mm) long. Further details of the flowers are unknown. The fruit, a capsule about 0.4 in (10 mm) long and 0.5-0.6 in (13-15 mm) wide, has carpels that are fused along almost their entire length. Each fertile carpel contains one or two glossy black seeds about 0.2 in (5 mm) long. The exocarp and endocarp are both hairless. M. ovalis is distinguished from other species of the genus by the almost entirely fused carpels of its capsule, its nonpersistent sepals and petals, and its well-developed petioles.

The species was described and named Pelea ovalis in 1944 from a specimen collected in the mountains above Hana on East Maui. He chose the specific epithet to refer to the shape of the leaves of the species. In 1989, the genus Pelea was synonymized with Melicope, resulting in the combination M. ovalis.

Habitat

M. ovalis typically grows in koa-and 'ohi'a-dominated montane wet forests at elevations of 2,800-4,700 ft (850-1,430 m). Associated species include Broussaisia arguta (kanawao), Cheirodendron trigynum ('olapa), and Perrottetia sandwicensis (olomea).

Distribution

M. ovalis has been found only on the Hawaiian island of Maui on the eastern and southeastern slopes of Haleakala. The only extant population was discovered in the late 1980s at Kipahulu Valley in Haleakala National Park. A more recent, limited reconnaissance suggests that, though uncommon, the species occurs over an area of at least several hundred hectares at elevations of 2,800-4,700 ft (850-1,430 m). A minimum of several hundred individuals exist. This species is believed to be substantially more common than M. balloui.

Threats

The modest numbers of individuals in the one surviving population of M. ovalis means that this limited gene pool might depress future reproductive vigor, while substantially increasing the chances for extinction from stochastic events. A single human-caused or natural environmental disturbance could destroy a significant percentage of the individuals remaining or even the entire population.

In comparison with other Melicope species in Hawaii, M. ovalis appears to be particularly vulnerable to alien black rats attacking its seeds. This vulnerability may occur because the relatively large size of the capsules and prolific fruiting of the species makes it more attractive to rodents than other Melicope species.

If uncontrolled, Hilo grass, Koster's curse, strawberry guava, kahili ginger, and Australian tree fern represent potential serious threats to the long-term survival of M. ovalis.

M. ovalis also appears to be more vulnerable than other Melicope species to native insects attacking its seeds. The endemic microlepidopteran is known to feed on the buds, flowers, and seeds of Melicope.

Conservation and Recovery

M. ovalis has so far not been propagated, although seeds of the species have recently been made available to the National Tropical Botanical Gardens. Protection of the Kipahulu Valley ecosystem by Haleakala National Park through construction of barrier fences, pig removal, and alien plant management provided a major action toward recovery of this species.

A search needs to be conducted for M. ovalis elsewhere on windward Haleakala, especially in the area where it was first found.

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
Telephone: (503) 231-6121
http://pacific.fws.gov/

Reference

U. S. Fish and Wildlife Service. 1997. "Recovery Plan for the Maui Plant Cluster." U. S. Fish and Wildlife Service, Portland, Oregon, 130 pp.