Lysimachia iniki is a rare species of flowering plant in the family Primulaceae known by the common names Wailua River yellow loosestrife and Wailua River island-loosestrife. It is endemic to Hawaii, where there is only one known occurrence existing on the island of Kauai. The plant was federally listed as an endangered species of the United States in 2010. When the plant was described there were at least 25 individuals. By 2010 there were 40 plants remaining in the single location where it is known to grow, by the "Blue Hole" at the headwaters of the north fork of the Wailua River.