Kamakahala

Labordia tinifolia var. wahiawaensis

Description

Labordia tinifolia var. wahiawaensis, a variety of kamakahala and a member of the logania family (Loganiaceae), is a shrub or small tree that reaches a height of 6.6-26.2 ft (2-8 m). The young branches are cylindrical or nearly so and hairless. The elliptic to lance-shaped leaves are usually 1.8-8.3 in (4.5-21 cm) long and 0.8-2 in (2-5 cm) wide. The membranous leaves are medium green, hairless, and the veins are not impressed on the upper leaf surface. Normally, nine to 12 hairless flowers are clustered on a downward curving inflorescence stalk 0.35-0.9 in (cm) long, each having an individual stalk 0.2-0.4 in (0.5-1 cm) in length. The pale yellowish green flower is narrowly urn-shaped and 0.7-0.75 in (1.8-1.9 cm) long. The tubular portion of the flower is 0.2-0.3 in (0.5-0.75 cm) long with long, white hairs inside, while the egg-shaped lobes are 0.07-0.09 in (0.18-0.23 cm) long. The egg-shaped fruit, a capsule 0.2-0.7 in (0.5-1.8 cm) long, usually has two valves and an apex with a beak 0.02-0.1 in (0.05-0.25 cm) long. Three varieties of L. tinifolia are recognized: var. lanaiensis on Lanai and Molokai, var. tinifolia on Kauai and four other islands, and var. wahiawaensis on Kauai (endemic to that island). Variety wahiawaensis is distinguished from the other two by its larger corolla. This species differs from others of the genus by having a long common flower cluster stalk, hairless young stems and leaf surfaces, transversely wrinkled capsule valves, and corolla lobes usually 0.1 in (0.25 cm) long.

Habitat

L. tinifolia var. wahiawaensis plants grow along streams in lowland wet forests dominated by 'ohi'a and often in association with 'olapa or uluhe. Plants found in association with this species include ha'iwale, hame, kopiko, manono, and Athyrium sp.

Distribution

L. tinifolia var. wahiawaensis, only known from the Wahiawa Drainage in the Wahiawa Mountains of Kauai, occurs at elevations from about 2,070-2,430 ft (631-741 m) on private land within a 0.5 by 0.75 mi (0.8 by 1.2 km) area. More than 100 plants were known from the area before Hurricane 'Iniki swept over Kauai in 1992. During a 1994 visit to the area, only 20-30 surviving individuals were found.

Threats

The primary threats to the remaining individuals of L. tinifolia var. wahiawaensis are competition with the alien plant strawberry guava, habitat degradation by pigs, trampling by humans, and a risk of extinction from naturally occurring events and reduced reproductive vigor due to the small number of individuals in the only known population.

L. tinifolia var. wahiawaensis has populations close to trails or roads that are easily accessible to possible overcollection by plant enthusiasts. These populations are also considered to be immediately threatened by recreational use in the areas in which they occur. Strawberry guava is known to pose a direct threat to the Wahiawa Mountains population, and thimbleberry threatens the Limahuli Valley population.

Hurricane Iniki destroyed more than 75% of all known L. tinifolia var. wahiawaensis plants through direct wind devastation and subsequent substrate subsidence; the severity of this damage could be repeated if future hurrincaes hit Kauai.

Conservation and Recovery

This species has been successfully propagated from seeds, and plants are in cultivation at Waimea Arboretum.

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

Reference

U.S. Fish and Wildlife Service. 1988. "Kauai II: Addendum to the Recovery Plan for the Kauai Plant Cluster." U.S. Fish and Wildlife Service, Portland, Oregon. 84+ pp.