Haha (Cyanea humboldtiana)
|Listed||October 10, 1996|
|Description||Leaf edges are hardened and have shallow, ascending rounded teeth; five to 12 flowers are arranged on a hairy, downward bending flowering stalk; berries are pale orange.|
|Habitats||Wet 'ohi'a-uluhe shrubland.|
|Threats||Habitat degradation by feral pigs, predation by rats; competition from alien plants; human disturbance.|
Cyanea humboldtiana, a member of the bellflower family, is an unbranched shrub with woody stems 3.2-6.6 ft (1-2 m) tall. The leaves are inversely egg-shaped to broadly elliptic, 7-18 in (17.8-45.7 cm) long and 2.8-6.3 in (7.1-16.0 cm) wide. The leaf edges are hardened and have shallow, ascending rounded teeth. Five to 12 flowers are arranged on a hairy flowering stalk that is downward bending and 3-10 in (7.6-25 cm) long. The dark magenta or white petals are 2.4-3 in (6.1-7.6 cm) long and hairy. The pale orange yellow berries are elliptic to inversely egg-shaped. This species differs from others in this endemic Hawaiian genus by the downward bending flowering stalk and the length of the flowering stalk.
Charles Gaudichaud-Beaupre collected a new lobelioid on Oahu on his third trip to Hawaii while a botanist on the vessel La Bonite. He later described the lobelioid and named it Rollandia humboldtiana. Other published names considered synonymous with R. humboldtiana include Delissea racemosa, R. humboldtiana forma albida, R. pedunculosa, and R. race-mosa. T. G. Lammers, Thomas Givnish, and Kenneth Sytsma merged the endemic Hawaiian genera, Cyanea and Rollandia, under the former name, publishing the new combination, C. humboldtiana. The specific epithet honors the German naturalist and explorer, Baron Alexander von Humboldt.
This species is usually found in wet 'ohi'a-uluhe shrubland from 1,800-3,150 ft (549-960 m) in elevation. Associated native plant taxa include ferns, alani, 'uki, kawa'u, and naupaka kuahiwi.
C. humboldtiana was known historically from 17 populations in the central portion to the southern end of the Koolau Mountains of Oahu. The three current populations occur on private, state, and federal land on the Omega U.S. Coast Guard Station. There were 125-225 total plants known from these locations in 1997—20 individuals at Konahuanui summit, 100-200 at Moanalua-Kaneohe summit, and less than five at Lulumahu Gulch.
Habitat degradation and destruction by feral pigs, potential predation by rats, competition with the alien plant Koster's curse, and a risk of extinction from naturally occurring events or through reduced reproductive vigor in very small populations are the major threats to C. humboldtiana. The Konahuanui summit population also is threatened by trampling by hikers.
C. humboldtiana is potentially threatened by feral pig predation because the species is not known to be unpalatable to pigs and they favor plants from the bellflower family for food. It is possible that rats eat the fruit of C. humboldtiana, a plant with fleshy stems and fruit that grows in areas where rats occur. The noxious shrub Koster's curse is a threat to this endangered species. Overcollection for scientific or horticultural purposes and excessive visits by individuals interested in seeing rare plants in their natural settings could seriously damage C. humboldtiana, whose populations are close to trails and roads, thus giving easy access to potential collectors.
C. humboldtiana has populations in recreational areas, near trails, and close to roads, making it very vulnerable to human disturbances.
Conservation and Recovery
This species is being propagated at the Lyon Arboretum.
U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
Eastside Federal Complex
911 N. E. 11th Ave.
Portland, Oregon 97232-4181
Telephone: (503) 231-6121
U.S. Fish and Wildlife Service. 1998. "Recovery Plan for Oahu Plants." U.S. Fish and Wildlife Service, Portland.