A perennial shrub endemic to the windward side of the island of Lanai. Only one subpopulation of 100 plants is currently known in an area of less than 10 km². When first discovered in 1987, this subpopulation consisted of 60–70 plants, but by the mid-1990s it had been more than halved. However, the population was subsequently fenced to protect the plants from introduced deer, and although there was abundant recruitment within the exclosure for a time, numbers undergo extreme fluctuations. There is also continuing decline due to the impacts of the deer, introduced mouflon sheep and alien plants, hence the listing as Critically Endangered.
Introduced deer, moufflon sheep, and invasive alien plants constitute the main threats. Overgrazing by cattle was also a problem in the past. Dry habitats in Hawaii have reduced by 90% from their original distribution and continue to decline dramatically.