''Sesbania tomentosa'', commonly known as Oahu riverhemp and ''ōhai'', is an endangered species of plant in the pea family, Fabaceae, that 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 else ...

to the main Hawaiian Islands as well as

Nihoa Nihoa (; haw, Nīhoa ), also known as Bird Island or Moku Manu, is the tallest of ten islands and atolls in the uninhabited Northwestern Hawaiian Islands (NWHI). The island is located at the southern end of the NWHI chain, southeast of ...

and Necker Island. It inhabits low shrublands and, rarely,

dry forests The tropical and subtropical dry broadleaf forest is a habitat type defined by the World Wide Fund for Nature and is located at tropical and subtropical latitudes. Though these forests occur in climates that are warm year-round, and may receive ...

, at elevations from sea level to . Associated native plant species include akiaki (''

Sporobolus virginicus ''Sporobolus virginicus'', known by numerous common names including seashore dropseed, marine couch, sand couch, salt couch grass, saltwater couch, coastal rat-tail grass, and nioaka, is a species of grass with a wide distribution. Description ...

''), ilima (''

Sida fallax ''Sida fallax'', known as yellow ilima or golden mallow, is a species of herbaceous flowering plant in the ''Hibiscus'' family, Malvaceae, indigenous to the Hawaiian Archipelago and other Pacific Islands. Plants may be erect or prostrate and are ...

''), naupaka kahakai (''

Scaevola taccada ''Scaevola taccada'', also known as beach cabbage, sea lettuce, or beach naupaka, is a flowering plant in the family Goodeniaceae found in coastal locations in the tropical areas of the Indo-Pacific. It is a common beach shrub throughout the Ar ...

''), and pili (''

Heteropogon contortus ''Heteropogon contortus'' is a tropical, perennial tussock grass with a native distribution encompassing Southern Africa, southern Asia, Northern Australia, Oceania, and southwestern North America. The species has also become a naturalised weed i ...

''). Off-road vehicles,

wildfire A wildfire, forest fire, bushfire, wildland fire or rural fire is an unplanned, uncontrolled and unpredictable fire in an area of combustible vegetation. Depending on the type of vegetation present, a wildfire may be more specifically identi ...

s, grazing, and alien species competition have destroyed their habitat on the main islands, but they are still quite common on Nihoa and Necker. At least 2000 specimens grow on Nihoa, while there are far less on Necker. ''Ōhai'' is highly polymorphic, exhibiting broad variations in color and shape. Plants that grow on Nihoa have reddish-orange flowers and young leaflets that are relatively hairless. Necker plants have salmon to orange colored-flowers, and leaflets that are very hairy. A form that grows as a standing tree exists on Molokai. ''Ōhai'' grows as a prostrate shrub with semi- glaucous hairless leaves on the southernmost tip of the

island of Hawaii Hawaii ( ; haw, Hawaii ) is the largest island in the United States, located in the state of Hawaii. It is the southeasternmost of the Hawaiian Islands, a chain of volcanic islands in the North Pacific Ocean. With an area of , it has 63% of th ...

Ka Lae Ka Lae ( haw, the point), also known as South Point, is the southernmost point of the Big Island of Hawaii and of the 50 United States. The Ka Lae area is registered as a National Historic Landmark District under the name South Point Complex. ...

References

External links

* * Faboideae Plants described in 1838 Endemic flora of Hawaii {{Faboideae-stub