''Lysimachia filifolia'' is a rare species of flowering plant in the

Primulaceae The Primulaceae , commonly known as the primrose family (but not related to the evening primrose family), are a family of herbaceous and woody flowering plants including some favourite garden plants and wildflowers. Most are perennial though som ...

known by the common name Wailua River yellow loosestrife.USDA Plants Profile
/ref> 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 else ...

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 state ...

, where there are two populations on

Oahu Oahu () ( Hawaiian: ''Oʻahu'' ()), also known as "The Gathering Place", is the third-largest of the Hawaiian Islands. It is home to roughly one million people—over two-thirds of the population of the U.S. state of Hawaii. The island of O� ...

and one on Kauai. It is a federally listed endangered species of the United States. This is a small shrub growing up to about half a meter in maximum height. The leaves are very narrow to threadlike and the flowers are reddish purple.''L. filifolia''.
The Nature Conservancy. The plant grows on the faces of

waterfall A waterfall is a point in a river or stream where water flows over a vertical drop or a series of steep drops. Waterfalls also occur where meltwater drops over the edge of a tabular iceberg or ice shelf. Waterfalls can be formed in severa ...

s in wet forest habitat.USFWS
''L. filifolia'' Five-year Review.
July 2009. There are about 130 individuals remaining on the island of Oahu, growing at waterfalls in the Koolau Range. There is a single population on Kauai, just discovered in 2008. Another population of plants on Kauai proved to be members of a different species, ''

Lysimachia pendens ''Lysimachia pendens'' is a rare species of flowering plant in the family Primulaceae known by the common name broad-leaf yellow loosestrife. It is endemic to Hawaii, where there is a single occurrence known on the island of Kauai.

''. This plant is threatened by the degradation of its habitat by

feral pig The feral pig is a domestic pig which has gone feral, meaning it lives in the wild. They are found mostly in the Americas and Australia. Razorback and wild hog are Americanisms applied to feral pigs or boar-pig hybrids. Definition A feral ...

s and non-native plant species such as mistflower (''Ageratina riparia''), ti (''Cordyline fruticosa''), and umbrella tree (''Schefflera actinophylla'').

References

filifolia Endemic flora of Hawaii Biota of Kauai Biota of Oahu Taxa named by Asa Gray {{Primulaceae-stub