fireweed

not listed

N5 - Secure

SNR - Unranked

not listed

Fireweed (ssp.circumvagum) is an erect, perennial, 12″ to 78″ tall forb that rises usually on a single aerial stem from a rhizome-like underground stem and fibrous roots. It often forms large colonies.

The stems are erect, usually unbranched, and round or somewhat angular in cross section. They are leafy and green, sometimes becoming reddish near the top in strong sunlight. They are hairless near the bottom, sparsely minutely hairy near and in the inflorescence.

The leaves are alternate, numerous, and crowded. They are on 1 ⁄16″ to ¼″ long leaf stalks. They are oblong lance-shaped or elliptic lance-shaped, 3½″ to 9″ long, and ⅝″ to 1¼″ wide. The leaf blades are wedge shaped at the base and blunt at the tip. The upper and lower surfaces are hairless except for minute hairs along the midvien, especially below. There is a prominent midvein and 10 to 25 lateral veins that run into a single submarginal vein. The submarginal vein and the lateral veins are distinct. The margins are more or less toothed.

The inflorescence is a 3″ to 8″ long, unbranched cluster (raceme) of up to 15 or more stalked flowers at the end of the stem. The flowers nod at the end of a long, magenta-colored stalk when in bud. They are spreading to almost erect when in bloom.

Each flower is ¾″ to 1½″ in diameter. There are 4 sepals, 4 petals, 8 stamens and 1 style. The sepals are spreading, narrowly lance-shaped, ⅜″ to ¾″ long, and similar in color but darker than the petals. The petals are pink to magenta, rarely white. They are 9 ⁄16″ to 1″ long and ¼″ to ⅝″ wide. They are narrowed at the base and broad near the tip. The stamens have long white filaments and dark magenta anthers. The style has a 4-lobed stigma.

The fruit is a straight, cylinder-shaped, 2″ to 3¾″long capsule with many seeds.

12″ to 78″

Pink or magenta

Fireweed (Chamaenerion angustifolium ssp. angustifolium) is a shorter plant, no more the 52″ tall, The stems are hairless below the inflorescence. The leaves are stalkless or almost stalkless, smaller, and hairless on the midvein above and below. The leaf blades are broadly angled to almost rounded at the base and tapered at the tip. The lateral veins are indistinct. The flower petals are much smaller.

Moist; roadside ditches, disturbed places, especially after a fire. Full or partial sun.

July to September

Sources

4, 7, 29, 30.

USDA PLANTS shows C. a. ssp. angustifolium very common in Minnesota, concurrent with the range of its parent species, and C. a. ssp. circumvagum present in just seven scattered counties. GRIN shows the situation reversed, with C. a. ssp. angustifolium native to Canada and the northwestern United States and possibly also to Minnesota. The map at left does not include the USDA PLANTS data.

Native

Species in the genus Chamaenerion were originaly placed in the genus Epilobium. A group of several species was later separated from Epilobium as the new genus Chamaenerion. Recently it was determined that the name Chamaenerion was invalid “because it was derived from pre-Linnean sources and is synonymous with Epilobium,” and the genus name was shortened to Chamerion. A more recent clarification of the internationational Code of Botanical Nomenclature (ICBN), now the International Code of Nomenclature (ICN), “correctly argued that the name of the segregated genus should be Chamaenerion.”

Today (2023) there is little agreement as to the proper placement of the group.

ITIS and USDA PLANTS use the name Chamerion angustifolium.

NCBI, GRIN, GBIF, BONAP, Tropicos, Flora of North America, and iNaturalist use the name Chamaenerion angustifolium.

Plants of the World Online and World Flora Online use the name Epilobium angustifolium.