|Listed||March 4, 1994|
|Description||Hairless tree with milky sap, lance-or ellipse-shaped toothless leaves arranged three or four per node, and open clusters of numerous, trumpet-shaped greenish white flowers.|
|Habitat||Koa-and-'ohi'a or lama-dominated montane mesic forests.|
|Threats||Competition from alien plants; browsing by feral goats; fire; limited numbers.|
Holei (Ochrosia kilaueaensis ) is a hairless tree, 49-59 ft (14.9-18 m) tall, with milky sap. The lance-or ellipse-shaped toothless leaves are arranged three or four per node, are 2.4-7.5 in (6.1-19.1 cm) wide, and have veins arising at nearly right angles to the midrib. Open clusters of numerous flowers have main stalks 1.8-2.5 in (4.6-6.4 cm) long. Each flower has a five-lobed calyx about 0.4 in (1 cm) long and a trumpet-shaped greenish white corolla with a tube 0.3-0.4 in (7.6-10.2 mm) long and lobes 0.5-0.6 in (1.3-1.5 cm) long. The fruit is a drupe thought to be yellowish brown at maturity, 1.8-1.9 in (4.6-4.8 cm) long, and 0.9-1.1 in (2.3-2.5 cm) wide. The species is distinguished from other Hawaiian species of the genus by the greater height of mature trees, the open flower clusters, the long flower stalks, and the larger calyx and lobes of the corolla.
Holei typically grows in koa-and-'ohi'a or lama-dominated montane mesic forests at elevations of 2,200-4,000 ft (671-1,219 m). Associated species include 'aiea, kauila, and kopiko.
Historically, this species has been collected on the northern slope of Hualalai and on the eastern slope of Mauna Loa. There may be an extant population located at Puu Waawaa on state land. The population was last collected by Q. Tomich on an unknown date, and the last known observation of the population was in the 1940s, so it may be extinct. The population in Hawaii Volcanoes National Park has not been observed since 1927, although the kipuka was intensively surveyed in 1992.
O. kilaueaensis has several major threats to its survivability, provided that the taxon remains extant. Feral goats browse and trample the native vegetation, disturbing substrate and understory and providing ample sites for weedy adventives such as Pennisetum setaceum (fountain grass). Competition from alien species is a major source of concern for this rare taxon. And drying stands of grass provide an excellent source for fire. In addition, predation of fruits by black rats is a potential problem.
Provided that this taxon persists, human impacts continue to be a serious threat to the species' survival. If this exceedingly rare taxon is extant, the extremely limited number of individuals reduces reproductive rates and increases the probability of extirpation by random events.
Conservation and Recovery
A thorough survey of the area where the last known O. kilaueaensis occurred is necessary. If the species is found, genetic material for maintenance of ex situ stock should be collected, the existing population protected, and eventual outplanting of propagated material in protected areas within its historic range pursued.
U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
Eastside Federal Complex
911 N. E. 11th Ave.
Portland, Oregon 97232-4181
Pacific Remote Islands Ecological Services Field Office
300 Ala Moana Blvd., Room 3-122
P. O. Box 50088
Honolulu, Hawaii 96850
Telephone: (808) 541-1201
Fax: (808) 541-1216
U. S. Fish and Wildlife Service. 4 March 1994. "Endangered and Threatened Wildlife and Plants; Determination of Endangered or Threatened Status for 21 Plants from the Island of Hawaii, State of Hawaii." Federal Register 59 (43): 10305-10325.