CPC Plant Profile: Koolau Eugenia
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Plant Profile

Koolau Eugenia (Eugenia koolauensis)

This shot is a closeup of the flower. Photo Credit: Waimea
  • Global Rank: G1 - Critically Imperiled
  • Legal Status: Federally Endangered
  • Family: Myrtaceae
  • State: HI
  • Nature Serve ID: 138020
  • Date Inducted in National Collection: 12/17/1990

Eugenia koolauensis is a member of the myrtle family (Myrtaceae). It is a small tree or shrub, and can reach 2 - 7 meters (7 - 23 feet) in height. Its branch tips are covered with dense brown hairs and their leathery oval leaves are densely hairy on the lower surface. From February to December, Eugenia koolauensis reveals its white flowers, which grow from the leaf axils on short stalks. Eugenia koolauensis was historically known from Maunaloa on western Moloka`i and from scattered areas on the island of O`ahu. Now it is known only from 8 populations on O`ahu. This species is severely threatened by its limited numbers, which was caused mainly by weed competition and the effects of feral pigs.

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  • 09/11/2020
  • Propagation Research

Propagation-seed (USFWS 1996)

Nature Serve Biotics
  • 05/02/2017

Endemic to the northern Koolau Mountains of Oahu and western Molokai. The species has not been observed on Molokai since the early 1900's. On Oahu, there are 6 current occurrences with a total of about 200 plants. Threats to the plant and its habitat include alien plants, feral pigs and human disturbance.

David Orr
  • 01/01/2010

Feral pigs. Alien plant species. Possibly fire. Human threat. Stochastic extinction due to small population size. (USFWS 1996)

David Orr
  • 01/01/2010

O`ahu-Papali Gulch, the north fork of Kamananui Stream, in the regions of Aina Haina and Hawaii Loa, and two disjunct populations in the southeastern Koolau Mountains. There are 8 populations remaining with less than 200 individuals (USFWS 2001) and (USFWS 1996).

David Orr
  • 01/01/2010

Propagation-seed (USFWS 1996)

David Orr
  • 01/01/2010

Weeding and some pig control (USFWS 1996). In May 2002, the U.S. Fish and Wildlife Service determined that a designation of critical habitat was prudent for this species. (USFWS 2002)

David Orr
  • 01/01/2010

Exclosures to protect wild plants from pigs. Weed control. Decrease human threat. Monitoring. (USFWS 1996)

David Orr
  • 01/01/2010

Propagation. Seed banking and germplasm preservation. Ex situ plantings at botanical gardens. Genetic studies. Physiological studies. (USFWS 1996)


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Taxon Eugenia koolauensis
Authority Degener
Family Myrtaceae
CPC Number 7615
ITIS 27194
Common Names Ko`olau eugenia | Koolau eugenia | nioi
Associated Scientific Names Eugenia koolauensis
Distribution On the island of O`ahu only. From Papali gulch, the north fork of Kamananui Stream, in the regions of Pupukea and Paumalu in the northern Koolau Mountains, Hawaii Loa and Aina Haina, and two disjunct
State Rank
State State Rank
Hawaii S1

This species exist in dry gulches and ridges in mesic forests dominated by Metrosideros polymorpha or Diospyros sp. From 57 to 437 m (187 to 1433 feet) in elevation (USFWS 2002) and (Wagner et al. 1999). Other associated plant species include Alyxia oliviformis, Bobea elaitor, Carex meyenii, Dicranopteris linearis, Myrsine lessertiana, Nestegis sandwicensis, Pleomele halapepe, Pouteria sandwicensis, Psydrax odorata, Rauvolfia sandwicensis, or Styphelia tameiameiae. (USFWS 2002).

Ecological Relationships

Reproductive cycles, longevity, specific environmental requirements, and limiting factors are all unknown (USFWS 1996).

Common Name Name in Text Association Type Source InteractionID
Lead Institution State Reintroduction Type Year of First Outplanting

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