No Common Name
|Listed||September 11, 1991|
|Description||Unbranched palm-like tree with a crown of large leaves and clusters of curved, white, tubular flowers.|
|Habitat||Moist forest understory.|
|Threats||Low numbers, feral pigs, alien plant species.|
Cyanea superba is a palm-like tree of the bellflower family that grows to a height of 20 ft (6.1 m). It is unbranched and crowned with a rosette of large oblanceolate leaves, 20-40 in (50.8-101.6 cm) long. Curved white tubular flowers hang in pendant clusters below the leaves. The flowering season of C. superba varies from year to year depending on precipitation; the normal range is from late August to early October. Flowering is generally at, its peak in early to mid-September. Fruits have been known to mature from two to five months, depending on the climatic conditions.
This species has been known by a variety of scientific names, including Lobelia superba, C. regina, Delissea regina, D. superba, and Macrochilus superbus.
C. superba grows in the understory of moist forests on western Oahu in well-drained, rocky soil at elevations between 1,760 and 2,200 ft (536.4 and 670.6 m). Canopy species such as kukui or candlenut (Aleurites moluccana) and Pisonia brunoniana keep the open understory in shade. The understory is heavily shaded by canopy trees, including ileurites moluccana (kukui) and P. brunoniana (papala kepan), but remains partially open. The understory is readily invaded by aggressive exotic plants. C. superba will not grow in direct sunlight.
C. superba ssp. regina had an historical presence in the southern Koolau mountains of Oahu, but this variety has not been collected since 1932. C. superba ssp. superba had an historical occurrence in the gulches of Makaleha on Mt. Kaala in the Waianae Mountains, although there were no documented sightings of the plant after its collection in 1870 until the species was rediscovered in 1971. This sole confirmed population on federal land and within Makua Military Reservation contained only five plants in 1998. A population of fewer than five plants was extirpated during the late 1990s on state land in Pahole Gulch. A third population, previously reported, appears to be based on a misidentification.
C. superba faces a number of threats. The extremely low number of known plants and their limited distribution makes the species vulnerable to extinction through unpredictable human or natural events. In addition, the species faces habitat degradation from the activities of feral pigs and competition from invasive non-native species. When surveyed in 1990, scientists observed feral pigs and noted the effects of rooting around plants in both populations. The greatest immediate threats to the survival of C. superba are the degradation of its habitat due to the introduction of alien plants such as strawberry guava and Christmas berry and predation by rats and slugs. Other major threats is the potential for destruction by wildfires generated in a nearby military firing range. The plants are confined to two small areas of 1,800 and 600 sq ft (167.2 and 55.7 sq m). The restricted range of this species makes it vulnerable to even small and localized environmental disturbances; a single incident could easily eliminate the entire remaining population. The very limited gene pool may also depress reproductive vigor.
Conservation and Recovery
Fencing and removal of feral pigs in the Pahole drainage, where the second population was located, was completed by the Division of Forestry and Wildlife in July 1997. Weeding of strawberry guava, Christmas berry, and Koster's Curse was conducted in the surrounding areas. Forty individuals grown from the Pahole Gulch population of C. superba were planted in three different exclosures in Pahole National Area Reserve. Seventeen individuals are in the Nike missile mid-elevation.
The army has plans to outplant four individuals in a fenced exclosure in Kahanahaiki on Makua Military Reservation. The wild population on army land is within a fenced exclosure. The army implemented an intensified rat control effort involving diphacinone bait blocks and snap-trapping during the 1997 fruiting season, which ensured production and protection of mature fruit.
This species is also being propagated at the Lyon Arboretum and the National Tropical Botanical Garden.
U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
Eastside Federal Complex
911 N. E. 11th Avenue
Portland, Oregon 97232-4181
U. S. Fish and Wildlife Service
300 Ala Moana Blvd., Rm. 6307
P.O. Box 50167
Honolulu, Hawaii 96850
Cuddihy, L. W., and C. P. Stone. 1990. Alteration of Native Hawaiian Vegetation: Effects of Humans, Their Activities and Introductions. University of Hawaii Cooperative National Park Resources Study Unit, Honolulu.
Lammers, T. G. 1988. "New Taxa, New Names, and New Combinations in the Hawaiian Lobelioideae (Campanulaceae)." Systematic Bontany 13 (4): 496-508.
Lammers, T. G. 1990. "Campanulaceae." In Manual of the Flowering Plants of Hawai ' i, edited by W. L. Wagner, D. R. Herbst, and S. H. Sohmer. University of Hawaii Press and Bishop Museum Press, Honolulu.
Tomich, P. Q. 1986. Mammals in Hawai ' i, second edition. Bishop Museum Special Publication 76. Bishop Museum Press, Honolulu.