No Common Name
|October 10, 1996
|Weakly climbing or sprawling subshrub; bears three to nine flowers.
|Lowland mesic or wet forest.
|Feral pigs; goats; competition with alien plant species; overcollection.
Alsinidendron viscosum, a member of the pink family, is a weakly climbing or sprawling sub-shrub. The stems are 2-9.8 ft (0.6-3 m) long and densely covered with fine glandular hairs throughout. The thin and membranous leaves are narrowly elliptic and are 1-2 in (2.5-5 cm) long and 0.3-0.7 in (0.8-1.8 cm) wide. Usually three to nine flowers are arranged in loose clusters with stalks 0.8-1.4 in (2-3.5 cm) long. The four sepals are white, thin, and membranous, remaining so at maturity. The outer two sepals greatly overlap the inner ones. The sepals are oblong in shape and 0.3 in (7.5 mm) long, but enlarge to approximately 0.5 in long in fruit, completely enclosing the fruit at maturity. The stamens are sparsely fused at the base and the basal outgrowths are about 0.1 in (2.5 mm) long, nearly as wide, and two-toothed. The fruits are egg-shaped capsules, 0.3-0.5 in (7.5-13 mm) long, and opening by five to seven valves. The seeds are dark reddish-brown, and approximately 0.03 in (7.5 mm) long with a minutely hairy surface. This species is distinguished from others in this endemic Hawaiian genus by the weakly climbing or sprawling habit, the color of the sepals, the number of flowers per cluster, and the size of the leaves. A. viscosum is closely related to A. lychnoides, which differs primarily in having wider leaves and more capsule valves and flowers per cluster.
A. viscosum is typically found at elevations of 2,700-3,510 ft (820-1,070 m), on steep slopes in koa-'ohi'a lowland mesic or wet forest. Associated plant species include Alyxia oliviformis (maile), Bobea sp. ('ahakea), Carex sp., Dodonaea viscosa ('a'ali'i), Ilex anomala ('aiea), Melicope sp. (alani), Pleomele sp. (hala pepe), and Psyhotria sp. (kopiko).
Historically, A. viscosum was known from the Kaholuamano, Kokee, Halemanu, Nawaimaka, and Waialae areas of the northwestern portion of the Hawaiian island of Kauai. This species, unseen since Charles Noyes Forbes made his 1917 collection near Kauaikinana in Kokee, was finally rediscovered in 1991, when Steven Perlman and Kenneth Wood of Hawaii Plant Conservation Program discovered a population of 11 mature plants on the ridge between the Waialae and Nawaimaka Valleys. Another 20-30 plants were discovered in 1993 in the same general area on a north-facing ridge in Nawaimaka Valley. In 1992, Timothy Flynn and David Lorence of the National Tropical Botanical Garden located 10 plants along the Mohihi-Waialae Trail. The two known populations—two subpopulations in Nawaimaka Valley and one population on the Mohihi-Waialae Trail—total 40-60 mature plants on state-owned land. One population is within the Alakai Wilderness Preserve.
The major threats to A. viscosum are the destruction of habitat by feral pigs and goats; over-collection; competition with the alien plant species prickly Florida blackberry, lantana, and molasses grass; and a risk of extinction from naturally occurring events and reduced reproductive vigor due to the small number of extant populations and individuals.
All known populations of A. viscosum are threatened by feral pigs. The Waialae and Nawaimaka Valley populations are threatened by goats. A. viscosum is not known to be unpalatable to goats or deer, so predation is a probable threat where these animals have been reported.
With populations close to easily accessible trails and roads, this species is vulnerable to overcollection from plant enthusiasts.
The aggressive and thicket-forming shrub lantana threatens populations of A. viscosum. Prickly Florida blackberry threatens the Waialae-Nawaimaka population and molasses grass threatens the largest population in the Waiale-Nawaimaka Valley.
Conservation and Recovery
The State of Hawaii's Division of Forestry and Wildlife and the U. S. Fish and Wildlife Service fenced the Nawaikama population of A. viscosum in 1998 to protect it from imminent destruction by goats.
More than 5,000 seeds were in storage at the National Tropical Botanical Garden in 1997. Seed germination tests, however, have indicated that less than 1% of the seeds germinate after only one year in storage, so the seed stock may not be viable. The U. S. Department of Agriculture's National Seed Storage Laboratory is testing this species for potential cryopreservation as a method of long-term storage.
Lyon Arboretum is propagating this species by tissue culture, a method of sprouting roots and shoots from meristematic tissue by placing the tissue on a medium and applying a growth hormone. No additional species-specific conservation efforts have been undertaken.
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
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, Oreg. 84+ pp.