Rare plant program report highlights recovery, struggles of Hawaiian plants

Two native plant species thought to be extinct were rediscovered in Hawaii in 2021, according to a report from the state’s Rare Plant Program, joining a list of other species that continue to struggle to stay alive.

The program, under the state Department of Land and Natural Resources’ Division of Forestry and Wildlife, highlighted more than a dozen rare Hawaiian plants that it, along with the University of Hawaii’s Plant Extinction Prevention Program, try to protect in a state dubbed as the “Endangered species capital of the world.”

According to a report providing Rare Plant Program highlights, the native fern Adenophorus periens, which was thought to be extinct, was rediscovered by PEPP on Kauai. Since then, a dozen small plants were found growing on the trunks of native trees in three locations.

A new Schiedea species, which belongs to the carnation family, was discovered by DOFAW staff near Laupahoehoe on Hawaii island. A single plant was found in 2019, but “disappeared” when botanists returned to the site. The soil was collected and a few months later the seedlings emerged and began growing. A new name for the species will be announced this year.

The report notes the struggles of native plants on the brink of extinction, including two species whose last individuals died in the wild. The last wild and mature plant of Urera kaalae, a tree on Oahu that’s part of the nettle family, died, but more than 2,000 plants were planted into protected areas in the Waianae mountains.

Similarly, the last wild plant of a Kadua cordata variant died. Seeds of the shrub, which is a member of the coffee family, that grows on Lanai are stored in seed banks at the National Tropical Botanical Garden have been withdrawn to grow on Maui.

Other highlighted species in the report include Portulaca molokiniensis, a succulent found only on Maui Nui that is being cultivated at native plant gardens, and only 50 plants remain in the wild. On Kahoolawe more than 600 seeds of Sesbania tomentosa, or ohai, that were collected from wild plants were planted into the Kamohio watershed by a Kahoolawe Island Reserve Commission team.

On Lanai, new populations of two critically endangered plants in the bellflower family, a Cyanea lobata subspecies and Cyanea gibsonii were discovered. On Molokai, helicopter surveys along the island’s northern coast found numerous landslides after heavy rains stripped sea cliffs of their vegetation and a decline of the native Brighamia rockii, another plant in the bellflower family. Fewer than 10 individuals are left in the wild, so plants are being protected and hand-pollinated.