Ha'iwale

Cyrtandra polyantha

Description

This ha'iwale (Cyrtandra polyantha ) is an un-branched or few-branched shrub 3-10 ft (0.9-3.0 m) in height. Its leathery, elliptic, unequal leaves are 2.0-6.3 in (5.1-16.0 cm) long, 0.7-2.0 in (1.8-5.1 cm) wide, and attached oppositely along the stems. The upper surface of the leaves is conspicuously wrinkled and usually hairless, with the lower surface moderately to densely covered with pale brown hairs. Seven to 12 flowers are grouped in branched clusters in the leaf axils. The white petals, fused to form a cylindrical tube about 0.5 in (1.3 cm) long, emerge from a radially symmetrical calyx 0.2 in (5.1 mm) long, that is cleft from one-half to two-thirds its length. Each calyx lobe, narrowly triangular in shape, is sparsely hairy on the outside and hairless within. The fruits are white oval berries about 0.6 in (1.5 cm) long that contain many seeds about 0.02 in (0.5 mm) long. C. polyantha is distinguished from other species in the genus by the texture and hairiness of the leaf surfaces, and the length, shape, and degree of cleft of the calyx. This species differs from C. crenata by the lack of short-stalked glands and by its leathery leaves, opposite leaf arrangement, and radially symmetrical calyx.

Habitat

C. polyantha is believed to remain on ridges of disturbed mesic valleys in the 'ohi'a forests at elevations between 1,600 and 2,000 ft (487.7 and 609.6 m). Associated plants would include 'uki, uluhe, kanawao, pilo, and kopiko.

Distribution

Historically, C. polyantha was known from the Kalihi region and from Kulepiamoa Ridge above Niu Valley on the leeward (southwest) side of the southern Koolau Mountains. Two populations, located farther south on Kuliouou summit ridge and at the northwest head of Hahaione Valley, are believed to be extant and are approximately 1 mi (1.6 km) apart on private and state land. The Hahaione Valley population has not been visited within the past 50 years; it is not known how many individuals remain. Only five individuals remained in the Kuliouou summit ridge population when it was last observed in 1993.

Threats

The primary threats to C. polyantha are habitat degradation, predation by pigs, suspected predation by rats and slugs, and competition from invasive alien plants such as strawberry guava and invasive grasses. Additionally there are high risks of reduced reproductive vigor or stochastic extinction due to the small number of surviving individuals and their restricted distribution.

Conservation and Recovery

Surveys of appropriate habitat in historical locations are needed to determine if any other extant populations of C. polyantha exist. Hahaione Valley should also be revisited to determine if a population still exists there.

Enclosures should be constructed around the extant populations to reduce impacts from feral pigs. Subsequent control or removal of pigs from these areas will alleviate their impact on native ecosystems. C. polyantha may be seriously threatened by rat predation. A management plan to control rats should be developed and implemented. This should include the use of the currently approved diphacinone bait blocks and ultimately a more broadscale method such as aerial dispersal of rodenticide.

To prevent possible extinction of C. polyantha, propagation material from the one confirmed surviving population and the possibly surviving second population should be collected immediately for attempts at protected cultivation.

Contacts

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/

Senior Resident Agent Office
U.S. Fish and Wildlife Service
300 Ala Moana Boulevard, Room 7-235
P.O. Box 50223
Honolulu, Hawaii 96850-5000
Telephone: (808) 541-2681
Fax: (808) 541-3062

Reference

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