Fireweed

Description

Chamaenerion is a genus of flowering plants in the family Onagraceae (the evening primrose or willowherb family). It has sometimes been included in the genus Epilobium. Members of the genus may be called willowherbs (along with Epilobium), or fireweeds, based on a common name used for C. angustifolium. They are upright herbaceous perennials, growing from a woody base or from rhizomes, with racemes of usually purple to pink flowers. All species are found in the northern hemisphere. Most occur in moist habitats; C. angustifolium is the exception, favouring disturbed ground. Chamaenerion species are upright herbaceous perennials with either unbranched stems or, much less often, slightly branched stems. They either have a woody base or grow from rhizomes. The leaves are generally spirally arranged on the stems and are usually narrow, rarely ovate. The inflorescence is a simple or slightly branched raceme. Individual flowers have four petals that are rose-purple to pink, rarely white. The petals are free at the base rather than united in a floral tube, as in Epilobium. The lower petals are narrower than the upper ones, making the flower radially unsymmetric (zygomorphic). There are eight more-or-less equally sized stamens, and a long, four-lobed style. The fruit is a long, thin, four-chambered (loculicidal) capsule that splits to reveal the many seeds. The seeds have a tuft of hairs at one end. Nomenclatural issues were reviewed by Alexander N. Sennikov in 2011. Although pre-Linnaean authors had used the name Chamaenerion, which may have originated as early as 1561, in 1753 Carl Linnaeus preferred Epilobium. Some authors continued to use Chamaenerion (or the alternative spelling Chamaenerium), but this name was not published legitimately under the International Code of Nomenclature for algae, fungi, and plants (ICN) until Jean-François Séguier did so in 1754. It was assumed by some later authors that Séguier's name was a superfluous replacement for Linnaeus' Epilobium, but Sennikov argues that a strict application of the ICN shows that it was legitimate. Ludwig K.G. Pfeiffer in 1873 used Chamaenerion in a more restricted sense than Linnaeus' Epilobium, designating Epilobium angustifolium L. as the type species. Thus the correct name for a genus separated from Epilobium and including Linnaeus' Epilobium angustifolium is Chamaenerion.