Endangered Species in the Pacific Islands
Recovery Plan for Kokia cookei
Kokia cookei, also known by its common Hawaiian name as Koki‘o, is a small deciduous (sheds seasonally or by stages) tree. The only wild individual of this century was about 10 feet in height.
This tree is known only from the island of Moloka‘i and has been described as the rarest plant in the world. When it was discovered in the 1860s, only three trees of the species were found. By the 20th century, only a single wild tree of K. cookei could be found. The species was wiped out from the wild in 1918.
Currently, there are no naturally occurring populations. The species exists only in cultivation grafted onto root stock of other endangered Kokia species.
Kokia cookei - Photo credit Dr. Carr/University of Hawai‘i
Habitat & Distribution:
Historically, K. cookei was found in the wild only in remnant dryland forest near Mahana, northeast of Pu‘u Nana, western Moloka‘i, at approximately 660 feet. The former habitat of K. cookei appears most similar to modern dryland forest at Kanepuu, Lana‘i, and leeward (northeast) Haleakala, Maui, at 1,000-2,000 feet elevation. Today, this tree is extinct in the wild and is only known in cultivation.
K. cookei was added to the Federal list of endangered and threatened species in 1979. Historically, the reasons for the decline and eventual extinction of this tree were habitat conversion, introduced grazing
mammals, loss of native pollinators, and seed predation by insect larvae. The current threats are low number of individuals and populations, lack of naturally rooted plants, and lack of viable seed production.
The State of Hawai‘i has tried five types of propagation with K. cookei seeds; cuttings; grafting; tissue culture; and air layering. Considerable effort to propagate this tree has been carried out by several private
individuals and nongovernmental organizations. Lyon Arboretum has been able to propagate a few individuals from immature seeds in tissue culture, but efforts to propagate and reintroduce seedlings so far have been unsuccessful.
Despite the heroic efforts to save this species, K. cookei is not safe from the threat of extinction. The recovery plan identifies three essential goals that must be met to reduce the chances of random naturally
occurring events causing the extinction of this tree: increase the number of individuals and natural populations, produce K. cookei plants that produce viable seeds, and reestablish the species in native habitat that can sustain natural reproduction of the species.