''Melicope quadrangularis'', also called four angle melicope or four-angled pelea, is a species of

plant Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclud ...

in the family Rutaceae. It is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to the

Hawaiian Islands The Hawaiian Islands ( haw, Nā Mokupuni o Hawai‘i) are an archipelago of eight major islands, several atolls, and numerous smaller islets in the North Pacific Ocean, extending some from the island of Hawaii in the south to northernmost Kur ...

, where it is known only from the island of

Kauai Kauai, () anglicized as Kauai ( ), is geologically the second-oldest of the main Hawaiian Islands (after Niʻihau). With an area of 562.3 square miles (1,456.4 km2), it is the fourth-largest of these islands and the 21st largest island ...

.''Melicope quadrangularis''.
The Nature Conservancy. It is threatened by

habitat loss Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby ...

. The

type specimen In biology, a type is a particular wiktionary:en:specimen, specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to a ...

of this species was collected in 1909. The plant was not seen again, and was presumed

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

, until 1991 when it was rediscovered. At that time there were 13 plants counted. This population had disappeared by 1998 and was likely destroyed in Hurricane Iniki.USFWS
''Melicope quadrangularis'' Five-year Review.
August 2010. By 2010 no additional plants had been discovered, there are none growing in cultivation, and there are no seeds in storage. However, there may be specimens still alive in unsurveyed areas.

References

quadrangularis Endemic flora of Hawaii Biota of Kauai Taxonomy articles created by Polbot {{Rutaceae-stub