Wikstroemia uva ursi A. Gray. is a densely branching shrub, endemic to the Hawaiian Islands. It reaches up to 1.5 meters in height, but in cultivation it often grows higher. The bark is fibrous and when a branch is broken off, the bark often peels.
The leaves are simple and often thick and firm with scattered hairs and has a pale green color with an elliptic, ovate to orbicular or obovate shape. The size of the leaves is varying in length between 0.9 to 5 cm and width between 0.5 to 3.8 cm and the veins are visible and glabrous. The apex of the leaf is rounded to acute and the base is cuneate to rounded. The flowers are perfect or unisexual and yellow, sometimes with a green tint. Flowers glabrous, puberulent or with scattered hairs, with peduncles between 1 mm and 6 mm. Fruit is red, varying between bright red and crimson red, with an ellipsoid shape between 8 to 11 mm long and 5 to 10 mm in diameter.
The species includes two varieties:
Wikstroemia uva-ursi var. kauaiensis is a spreading and often prostate shrub with reddish brown young branches. Stems are robust and leaves are up to 4 cm long and 3 cm wide. This variety is only native to Kaua?i.
Wikstroemia uva-ursi var. uva-ursi is a densely branching and sprawling shrub with young branches gray to reddish brown or yellow. Branches are slender and the leaves are up to 5 cm long and 3.8 cm wide. This variety is growing on O?ahu, Moloka?i and Maui.
This species information has been compiled by Louise Winther for NTBG, 2022.
References:
Hillebrand, W. (1888). Thymelaeaceae. In Flora of the Hawaiian islands: a description of their phanerograms and vascular cryptograms (pp. 383–388). Williams & Norgate.
Peterson, B. (1999). Thymelaeaceae. In W. L. Wagner, D. R. Herbst, & S. H. Sohmer (Eds.), Manual of the Flowering Plants of Hawai’i (pp. 1282–1291). Bernice Pauahi Bishop Museum Special Publication, 2 volumes.
The species is grown for its ornamental properties in the Hawaiian Islands. Can easily be grown from seeds, cuttings, or air-layers; great plant for water-saving gardening; sprouts after 1 month or more; seedlings are hardy and resistant to fungal rot, diseases, and largely immune to insect attack; initial growth is slow. See further propagation details and references in the Hawaiian Native Plant Propagation Database.
References:
Bishop Museum (2022). ‘akia kauhi, ‘akia manolo in Hawaiian Ethnobotany Online Database. http://data.bishopmuseum.org/ethnobotanydb/ethnobotany.php?b=d&ID=akia
Bornhorst, H. L. (1996). Growing native Hawaiian plants: a how-to guide for the gardener. Honolulu: The Bess Press. p. 25-26.
Culliney, J. L., and B. P. Koebele. (1999). A native Hawaiian garden: how to grow and care for island plants. Honolulu: University of Hawai‘i Press. p. 16-17, 43-46.
Hawaiian Native Plant Propagation Database.
Native Plants Hawai‘i.
Wikstroemia uva-ursi is also known as the Hillside False Ohelo, or under the Hawaiian name akia. Several species of the genus Wikstroemia endemic to the Hawaiian Islands are called akia – most often the name is referred to the species Wikstroemia uva-ursi and Wikstroemia oahuensis, but in other literature, the name comprises all species of the genus (Thaman, 1992; Bishop 2022)
References:
Bishop Museum (2022). Akia kauhi, Akia manolo in Hawaiian Ethnobotany Online Database. http://data.bishopmuseum.org/ethnobotanydb/ethnobotany.php?b=d&ID=akia
Thaman, R. R. (1992). Batiri Kei Baravi: The Ethnobotany of Pacific Island Coastal Plants. Atoll Research Bulletin, 361, 1–62. https://doi.org/10.5479/si.00775630.361.1
This taxon is managed and monitored by the Plant Extinction Prevention Program (www.pepphi.org). Field botanists of the National Tropical Botanical Garden (NTBG) have made seed collections over the years, and outplantings have occurred in NTBG's gardens on Kaua'i.
Reference:
Rønsted, N., Nyberg, D. & Wood, K. (2021). Wikstroemia uva-ursi var. kauaiensis. The IUCN Red List of Threatened Species 2021: e.T97910770A97910776. https://dx.doi.org/10.2305/IUCN.UK.2021-1.RLTS.T97910770A97910776.en
The sap—together with niu flesh (coconut, Cocos nucifera) and ko kea (white sugarcane, Saccharum officinarum)—is ingested with ‘uala (sweet potato, Ipomoea batatas) as a purgative. The leaves and leaf buds are mixed with the bark of ‘ohi‘a ‘ai (Syzygium malaccense) and ‘uhaloa root (Waltheria indica), flesh of niu, ko ‘aina kea (sugarcane variety, Saccharum officinarum). Pounded, water added, strained, and the liquid ingested for wai‘opua pa‘a and nae kulou (Chun 1994:23–25). See further details and references in the Hawaiian Ethnobotany Online Database.
Extracts of Wikstroemia uva-ursi showed antitumor activity in vitro with the active constituent being Wikstromol (Halehlian et al., 1979).
References:
Bishop Museum (2022) ‘akia kauhi, ‘akia manolo in Hawaiian Ethnobotany Online Database. http://data.bishopmuseum.org/ethnobotanydb/ethnobotany.php?b=d&ID=akia
Halehlian, J., Runkel, R., Mueller, N., Christopherson, J., Kratochvil, P., Benagiano, G., Kincl, F. A., Chien, Y. W., & Lamhert, J. (1979). Wikstromol, antitumor lignan from Wikstroemia foetida var. oahuensis A. Gray and Wikstroemia uva-ursi A. Gray (Thymelaeaceae). Pharmacol. Biochem. Rehau, 63(2), 541. https://doi.org/10.1002/jps.2600680545
The plant has a long history of being poisonous, even though it is still not fully understood (Peterson, 1999). Several species in the Thymelaeaceae and species in the genus Wikstroemia produce of poisonous compounds. Thus, it is expected that plant-material from Wikstroemia uva-ursi could be poisonous to a certain degree for humans.
Reference:
Peterson, B. (1999). Thymelaeaceae. In W. L. Wagner, D. R. Herbst, & S. H. Sohmer (Eds.), Manual of the Flowering Plants of Hawai'i (pp. 1282–1291). Bernice Pauahi Bishop Museum Special Publication, 2 volumes.
Endemic to the Hawaiian Islands.
Hawaiian species of the genus Wikstroemia has been mixed in a drink for a deadly cocktail used for suicide or as execution of criminals (Medeiros et al., 1998)
Reference:
Medeiros, A. C., Davenport, C. F., & Chimera, C. (1998). Auwahi: Ethnobotany of a Hawaiian dryland forest. In: Cooperative National Park Resources Studies Unit, University of Hawai'i at Manoa, Department of Botany.
IUCN Status: Critically Endangered (CR): Estimated total population is 146 individuals among 6 subpopulations. Wikstroemia uva-ursi var. kauaiensis is assessed as Critically Endangered under criterion B as it has an (B2) area of occupancy (AOO) of 8 km2, (a) occurs in only 2 locations and is severely fragmented, and (b) has a continuing decline in (i) extent of occurrence, (ii) area of occupancy, (iii) area, extent and/or quality of habitat, (iv) number of subpopulations, and (v) number of mature individuals.
Federal Listing Status: Wikstroemia uva-ursi has not yet been identified by US Fish and Wildlife for protection under the Endangered Species Act.
Major threats to this taxon include direct competition by invasive non-native plants. Predation and habitat degradation by non-native animals, particularly pigs, goats, and rats are also a major threat. This taxon is vulnerable to stochastic disturbance events such as fires, landslides and hurricanes.
Reference:
Rønsted, N., Nyberg, D. & Wood, K. (2021). Wikstroemia uva-ursi var. kauaiensis. The IUCN Red List of Threatened Species 2021: e.T97910770A97910776. https://dx.doi.org/10.2305/IUCN.UK.2021-1.RLTS.T97910770A97910776.en
This species is cultivated as an ornamental several places on the Hawaiian Islands for the decorative foliage and the bright red fruits (Peterson, 1999)
As the bark is very fibrous, the plant is used for making ropes and a traditional fabric of Hawaii called kapa. It has furthermore been used as a purgative and laxative in smaller doses (Peterson, 1999).
On the Hawaiian Islands, the plant has for hundreds of years being used under a traditional fishing method called hola. The method comprises using the plant as poison for stunning the fish.
Wikstroemia uva-ursi were collected and brought near a small pool. Right before using, the plants were pounded and crushed which made it easy to separate the bark from the rest of the plant. Then the bark was put in the pool and fish nearby would float to the surface being passive where they easily could be collected by the fishermen. The effect on the fish would wear off, approximately after an hour or two and the fish that were not collected were able to swim again (Stokes, 1921; Hanapi, 1996). Today, the chemistry behind this procedure is still not fully elucidated.
References:
Hanapi, R. H. (1996). Kahua kukui: Ethnobotany of the Hawaiians. Department of Parks and Recreation.
Stokes, J. F. (1921). Fish Poisoning in the Hawaiian Islands: With notes on the custom in southern Polynesia. Bishop Museum Press.
Peterson, B. (1999). Thymelaeaceae. In: W. L. Wagner, D. R. Herbst, & S. H. Sohmer (Eds.), Manual of the Flowering Plants of Hawai'i (pp. 1282–1291). Bernice Pauahi Bishop Museum Special Publication, 2 volumes.
An ongoing research project at National Tropical Botanical Garden is exploring the chemical diversity of Wikstroemia and an NSF funded collaborative project is investigating the phylogeny (origin, evolution and relationships) of Wikstroemia.
We currently have 10 herbarium specimens for Wikstroemia uva-ursi in our collection. Click on any specimen below to view the herbarium sheet data.
