Chamerion angustifolium, commonly known as Fireweed (mainly in North America), Great willow-herb (some parts of Canada), or Rosebay willowherb (mainly in Britain), is a perennial herbaceous plant in the willowherb family Onagraceae. The species name Angustifolium (narrowleaved) is constructed from the Latin words angustus meaning narrow and folium meaning leaved or leaf. It is native throughout the temperate Northern Hemisphere, including large parts of the boreal forests. This herb is often abundant in wet calcareous to slightly acidic soils in open fields, pastures, and particularly burned-over lands; the name Fireweed derives from the species' abundance as a coloniser on burnt sites after forest fires. Its tendency to quickly colonize open areas with little competition, such as sites of forest fires and forest clearings, makes it a clear example of a pioneer species. Plants grow and flower as long as there is open space and plenty of light. In Russia, its leaves were traditionally used as a tea, before the introduction of tea from China starting in the 17th century, it was greatly valued and was exported in large quantities to Western Europe as Koporye tea, Russian tea or Ivan Chai. Today, Koporye tea is still commonly sold and consumed in Russia, though it is not nearly as popular as it was in Pre-Soviet Russia. The young leaves, shoots and flowers of narrow-leaved fireweed are edible, and the flowers are used to make fireweed jelly. Yupik eskimos preserved the stems in seal oil in order to eat them year-round, and they used the tough outer stem to make fishing nets. Fireweed also has many uses in traditional medicine. Fireweed is the floral emblem of Yukon.