New plant species unique to Hawaiʻi discovered in remote West Maui forest

A unique plant first seen in the high forests of West Maui in 2020 has now been officially recognized as a new Hawaiian species. The plant, now named Clermontia hanaulaensis, was found during routine surveys by botanist Hank Oppenheimer of the Plant Extinction Prevention Program, a partnership with DLNR and the University of Hawai‘i.

The species is only found in Hawai‘i and is likely unique only to the mountains of West Maui.

“I decided to just turn a different way and look over a ridge I hadn’t explored before and there they were,” said Oppenheimer. “They looked very different from other Clermontia.”

Botanists across the state studied the plant’s flower and leaf structure, comparing it to herbarium specimens and photos to attempt to confirm that it is a previously undiscovered species. The botanists also ruled out the possibility of the plant being a hybrid of other Clermontia species. The verdict is in, and it has been given its own name. While new to the world of modern recognition, it exists only as a small population with a limited range, so it’s already being proposed for critically endangered status.

The patch of this rare plant is currently the only known population, numbering just under 80 adults and 20 seedlings spread out in an area about the size of 10 football fields. Although they are not growing on protected state lands, the private landowner has been a longtime conservation partner.

Key threats to rare plants across Hawai‘i are introduced plants, slugs, pigs, and rats which eat seeds and fruit. On Maui, Axis deer pose additional threats. Clermontia are usually pollinated by native forest birds, which are absent at this population’s elevation due to mosquito-spread avian malaria. They usually grow as mid-canopy plants, under larger trees. A hurricane knocking down larger trees or a single fire could wipe out this newly discovered species.  

Clermontia is a genus of plants that evolved in Hawai‘i and is found nowhere else in the world. They grow as small shrub-like trees on the six largest islands from about 600 to 6,000 feet in elevation, in cloud forests, wet and mesic forests, bogs and shrublands.

Their long, paddle-shaped leaves grow atop branches that fork like a candelabra. Urban gardeners might compare the growth architecture to non-native plumeria, but Clermontia flowers are long, spreading tubes sheltered by their leaves above. This species flower is lavender and white.

Hawai‘i has 423 plant species listed as threatened and endangered. Because there are only about 100 of this rare species in the wild, PEPP has collected seeds and will continue to monitor the population to ensure its survival.