''Vigna owahuensis'' is a rare species of flowering plant in the legume family known by the common name Oahu cowpea.

Distribution

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 ...

Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only stat ...

, where it is known from seven small populations on the islands of

Molokai Molokai , or Molokai (), is the fifth most populated of the eight major islands that make up the Hawaiian Islands, Hawaiian Islands archipelago in the middle of the Pacific Ocean. It is 38 by 10 miles (61 by 16 km) at its greatest length an ...

Lanai Lanai ( haw, Lānai, , , also ,) is the sixth-largest of the Hawaiian Islands and the smallest publicly accessible inhabited island in the chain. It is colloquially known as the Pineapple Island because of its past as an island-wide pineapple pl ...

, and

Kahoolawe Kahoolawe (Hawaiian: ), anglicized as Kahoolawe (), is the smallest of the eight main volcanic islands in the Hawaiian Islands. Kahoolawe is located about southwest of Maui and also southeast of Lānaʻi, and it is long by wide, with a total ...

. Though it was described from a specimen collected on

Oahu Oahu () (Hawaiian language, Hawaiian: ''Oʻahu'' ()), also known as "The Gathering place#Island of Oʻahu as The Gathering Place, Gathering Place", is the third-largest of the Hawaiian Islands. It is home to roughly one million people—over t ...

it is now extirpated from that island. It was also known from

Niihau Niihau ( Hawaiian: ), anglicized as Niihau ( ), is the westernmost main and seventh largest inhabited island in Hawaii. It is southwest of Kauaʻi across the Kaulakahi Channel. Its area is . Several intermittent playa lakes provide wetland hab ...

Maui The island of Maui (; Hawaiian: ) is the second-largest of the islands of the state of Hawaii at 727.2 square miles (1,883 km2) and is the 17th largest island in the United States. Maui is the largest of Maui County's four islands, which ...

, and

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 ...

in the past. This plant grows in many types of shrubland and

grassland A grassland is an area where the vegetation is dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur natur ...

habitat, as well as in some cultivated areas. It occurs on

cinder cone A cinder cone (or scoria cone) is a steep conical hill of loose pyroclastic fragments, such as volcanic clinkers, volcanic ash, or scoria that has been built around a volcanic vent. The pyroclastic fragments are formed by explosive eruptions o ...

s and offshore islets and exposed

coral reef A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of colonies of coral polyps held together by calcium carbonate. Most coral reefs are built from stony corals, whose polyps cluster in groups. Co ...

s.''Vigna o-wahuensis''.
The Nature Conservancy.

Description

''Vigna owahuensis'' is an annual or perennial herb growing up to long. Each leaf has three hairy leaflets of widely varying shape and size. Flowers occur singly or in clusters of up to four. They are light yellow or greenish in color and are about long. The fruit is a long, thin

legume A legume () is a plant in the family Fabaceae (or Leguminosae), or the fruit or seed of such a plant. When used as a dry grain, the seed is also called a pulse. Legumes are grown agriculturally, primarily for human consumption, for livestock f ...

pod up to in length. The pod may be slightly inflated or not. It contains up to 15 gray or black beans around long.

Conservation

The species faces many threats, including loss of habitat to agriculture and development, degradation of the habitat by

exotic plants An introduced species, alien species, exotic species, adventive species, immigrant species, foreign species, non-indigenous species, or non-native species is a species living outside its native distributional range, but which has arrived there ...

and animals, and military activity. It is a federally listed

endangered species An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inv ...

of the United States.USFWS
Endangered status for 12 plants from the Hawaiian Islands.
''Federal Register'' November 10, 1994. There are fewer than 100 individuals in total remaining on four islands. Two of the seven populations are on Molokai, one occurring in a plantation of tropical ash and

pine trees A pine is any conifer tree or shrub in the genus ''Pinus'' () of the family Pinaceae. ''Pinus'' is the sole genus in the subfamily Pinoideae. The World Flora Online created by the Royal Botanic Gardens, Kew and Missouri Botanical Garden accepts ...

. As of the year 1994 there was only one plant known on Lanai. There are several individuals on Hawaii and Kahoolawe.

References

External links

USDA Plants Profile
{{Taxonbar, from=Q7928946 owahuensis Endemic flora of Hawaii