Chamerion angustifolium

fireweed

Onagraceae

The Basics

Taxonomy: Kingdom - Plantae (plants). Subkingdom - Tracheobionta (vascular plants). Superdivsion - Spermatophyta (seed plants). Division - Magnoliophyta (flowering plants). Class - Magnoliopsida (dicotyledons). Subclass - Rosidae. Order - Myrtales. Family - Onagraceae (evening primrose). Genus - Chamerion Raf. ex Holub (fireweed). Species - Chamerion angustifolium (L.)Holub (fireweed).

Ecology: Fireweed is an important colonizer following vegetation disturbances in temperate climates worldwide. Although the role of fireweed as an early seral species does not change, the length of time fireweed populations are present varies among ecosystems. Fireweed enters a disturbed community and rapidly becomes abundant. Fireweed colonizes recent alluvial deposits. It acts as a pioneer species on glacial moraines, establishing with willows (Salix spp.) on exposed gravel, sand, and silt bars. In succession on delta swamps in Michigan, the grass stage with bluejoint reedgrass and fireweed follows the sedge-mat stage. The grass stage is succeeded by a shrub stage. Fireweed is an indicator of a mid-seral stage of succession in the herb layer of the grand fir/Rocky mountain maple (Abies grandis/Acer glabrum) habitat type in central Idaho. It is an indicator of early seral stages in grand fir/blue huckleberry (Vaccinium globulare) habitat types.

Identification

Previously known as Epilobium angustifolium, Fireweed is a robust native perennial forb. It has fine roots and rhizomes that extend down vertically to 45 cm from the plant, with most growing between 0-15 cm deep. The single stems are from 1-2.7 m tall and may be very leafy. Leaves are 7-15 cm long. One plant may have 15 or more flowers. Young shoots were collected by Nuxalk Indians in British Columbia for food. Fireweed petals are made into jelly. Mature leaves are dried and used as tea. Roots are eaten raw by Siberian Eskimos.

Threats

Fireweed is a component of diverse ecosystems in boreal and temperate regions with variable fire regimes. Fireweed is primarily adapted to fire through its rhizomes and its prolific production of wind-dispersed seed.

Fire effects: Depending upon depth of rhizomes in the soil, fireweed is moderately susceptible to resistant to fire. Fire top-kills fireweed. Seed in the surface organic layers is killed by fire. Surviving fireweed rhizomes vigorously sprout after a fire. Twenty to thirty days after fires in July and August fireweed sprouted from rhizomes...Fireweed is an important off-site colonizer after fire. Often, it is not present on a site before a fire but establishes during the first postfire year.

Reproduction

Flowering and Fruiting - Each flower produces a capsule with 300 to 500 seeds. Seeds have a tuft of long hairs on one end..Fireweed is a prolific seed producer. One plant may produce about 80,000 seeds per year...Airborne seeds allow fireweed to establish rapidly. Fireweed seed hairs or plumes respond to humidity. Increased humidity causes a decreased plume diameter which results in reduced loft. This increases the chance that seeds are deposited in places with moisture adequate for germination.

Vegetative Reproduction - Vegetative reproduction is more prevalent than sexual reproduction.Fireweed readily sprouts from rhizomes following disturbance. Fireweed was a residual survivor on Mount St. Helens, Washington, following the 1980 volcanic eruption. Shoots sprouting from rhizomes are capable of very rapid growth; they may bloom within 1 month. Fragmentation of rhizomes stimulates shoot production. A 4-year-old rhizome was excavated and found to be 6.1 m long; it had 56 perennating buds.

Species Distribution

Citation

USDA Plant Database
USDA, NRCS. 2016. The PLANTS Database (http://plants.usda.gov, 4 February 2016). National Plant Data Team, Greensboro, NC 27401-4901 USA.

Flora of North America
Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico. 19+ vols. New York and Oxford.

Intermountain Herbarium
Consortium of Intermountain Herbaria. 2016. http//:intermountainbiota.org/portal/index.php. Accessed on February 04.

Burke Museum Plant Image Collection
The plant image collection at the Burke Museum, University of Washington.

Jepson Manual
The Jepson Manual: Vascular Plants of California. B.G. Baldwin, D.H. Goldman, D.J. Keil, R. Patterson, T.J. Rosatti, and D.H. Wilken [editors]. 2012. 2nd edition, thoroughly revised and expanded. University of California Press, Berkeley, CA., hardcover; 1600 pages. ISBN-13: 978-0520253124.