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

Myrsinaceae

Myrsinaceae, or the Myrsine family, is a rather large family from the order Ericales. It consists of 35 genera and about 1000 species....

 known by the common name Wailua River yellow loosestrife. It is endemic to Hawaii

Hawaii

Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...

, where there are two populations on Oahu

Oahu

Oahu or Oahu , known as "The Gathering Place", is the third largest of the Hawaiian Islands and most populous of the islands in the U.S. state of Hawaii. The state capital Honolulu is located on the southeast coast...

 and one on Kauai

Kauai

Kauai or Kauai, known as Tauai in the ancient Kaua'i dialect, is geologically the oldest of the main Hawaiian Islands. With an area of , it is the fourth largest of the main islands in the Hawaiian archipelago, and the 21st largest island in the United States. Known also as the "Garden Isle",...

. It is a federally listed endangered species

Endangered species

An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...

 of the United States.

This is a small shrub

Shrub

A shrub or bush is distinguished from a tree by its multiple stems and shorter height, usually under 5–6 m tall. A large number of plants may become either shrubs or trees, depending on the growing conditions they experience...

 growing up to about half a meter in maximum height. The leaves are very narrow to threadlike and the flowers are reddish purple. The plant grows on the faces of waterfall

Waterfall

A waterfall is a place where flowing water rapidly drops in elevation as it flows over a steep region or a cliff.-Formation:Waterfalls are commonly formed when a river is young. At these times the channel is often narrow and deep. When the river courses over resistant bedrock, erosion happens...

s in wet forest habitat.

There are about 130 individuals remaining on the island of Oahu, growing at waterfalls in the Koolau Range

Koolau Range

Koolau Range is a name given to the fragmented remnant of the eastern or windward shield volcano of the Hawaiian island of Oahu. It is not a mountain range in the normal sense, because it was formed as a single mountain called Koolau Volcano...

. 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

Lysimachia pendens is a rare species of flowering plant in the family Myrsinaceae known by the common name broadleaf 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 pigs and non-native plant

Introduced species

An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...

 species such as mistflower (Ageratina riparia), ti (Cordyline fruticosa), and umbrella tree

Schefflera actinophylla

Schefflera actinophylla is a tree in the Araliaceae family. It is native to tropical rainforests and gallery forests in Australia , New Guinea and Java. Common names include Umbrella Tree, Octopus Tree and Amate.-Description:S...

(Schefflera actinophylla).