Epilobium hornemannii
Hornemann’s willowherb

Alaska Wildflowers | Pink

Close-up of the tiny flowers of Hornemann's willowerb, latin name Epilobium hornemannii

Epilobium hornemannii
Hornemann’s willowherb

Common Names

épilobe d’Hornemann
Hornemann’s willowweed
Hornemann’s willowherb

Synonyms

none

Subspecies

Epilobium hornemannii ssp. behringianum
Epilobium hornemannii ssp. hornemannii

Genus: Epilobium
Family: Onagraceae
Order: Myrtales
taxonomic heirarchy

Duration – Growth Habit

Perennial – Forb/herb

Identification and Information

Epilobium hornemannii, commonly known as Hornemann’s willowherb, is a small perennial herb belonging to the Onagraceae (primrose) family. It grows from short, leafy stolons (runners) in clumps with erect stems up to 45 cm tall. The leaves are often opposite and lanceolate proximal to the inflorescence while alternate and ovate or egg-shaped distally. Leaf petioles are longer distally from the inflorescence, 3-9 mm long. Leaves are also simple, sparsely denticulate, sometimes with short, stiff hairs.



The inflorescence is an open, glandular, terminal raceme with erect or nodding flowers. The flowers are rose to pink, sometimes white, with 0.7-2.4 mm deep notches at the tip. The notched petals are 3-9 mm long, while the sepals are shorter, 2-4.5 mm long, and sometimes red-tipped. Flowers are perfect, with both male and female parts. Stamen filaments are cream or light pink with yellow anthers, and the styles are white or cream, 2-8mm long. The fruit is a 4-6.5 cm long linear capsule, and the seeds have tufts of white hair that help with dispersal by wind.

Two recognized subspecies are found in overlapping areas: E. hornemannii subsp. hornemannii with shorter petioles and sepals and E. hornemannii subs. behringianum, which has more leathery leaves and longer petioles and sepals. Subspecies hornemannii is more common at higher elevations, and subspecies hornemannii is more common at lower and maritime elevations. However, they may both be present at a wide range of elevations.

There are approximately 20 species of Epilobium in Alaska, many of which closely resemble each other and can be challenging to differentiate based on morphology alone.


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Uses

For information only (typically historical) – I take no responsibility for adverse effects from the use of any plant.

No traditional, medicinal, or culinary uses were found.


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Distribution and Habitat

Map data from the Global Biodiversity Information Facility (GBIF), NatureServe Explorer, and Kew

Epilobium hornemannii is common in western and northeastern North America, eastern Siberia, Greenland, Iceland, and Scandinavia.

It’s habitat includes meadows and tundra, alpine or montane zones, rocky slopes, meadows, floodplains, and river banks.

Classification

RankScientific Name (Common Name)
KingdomPlantae (plantes, Planta, Vegetal, plants)
SubkingdomViridiplantae (green plants))
InfrakingdomStreptophyta (land plants)
SuperdivisionEmbryophyta 
DivisionTracheophyta (vascular plants, tracheophytes)
SubdivisionSpermatophytina (spermatophytes, seed plants, phanérogames)
ClassMagnoliopsida 
SuperorderRosanae 
OrderMyrtales 
FamilyOnagraceae (evening primroses, onagres)
GenusEpilobium L. (willow weed, willowweed, willowherb)
SpeciesEpilobium hornemannii Rchb. (Hornemann’s willowweed, Hornemann’s willowherb)
 Direct Children:
SubspeciesEpilobium hornemannii ssp. behringianum (Hausskn.) Hoch & P.H. Raven (Hornemann’s willowherb)
SubspeciesEpilobium hornemannii ssp. hornemannii Rchb. (Hornemann’s willowherb)

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References and Further Reading

Guidebook

Pratt, V. E. (1989). Field Guide to Alaskan Wildflowers: Commonly Seen Along Highways and Byways (p. 15 genus only). Alaskakrafts, inc.

Brandenburg, D. M. 2010. National Wildlife Federation Field Guide to Wildflowers of North America. Sterling Publishing. (p. 360-361 genus only)

Johnson, D., Kershaw, L., & MacKinnon, A. (2020). Plants of the Western Forest: Alaska to Minnesota Boreal and Aspen Parkland (3rd ed., p. 150 genus only). Partners Publishing. ISBN 978-1772130591.

Classification and Taxonomy

Integrated Taxonomic Information System (ITIS). (n.d.). Epilobium hornemannii. Retrieved May 5, 2024, from https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=27306

Canadensys. (n.d.). Epilobium hornemannii. Retrieved May 5, 2024, from https://data.canadensys.net/vascan/taxon/6778

Catalogue of Life. (n.d.). Epilobium hornemannii. Retrieved May 5, 2024, from https://www.catalogueoflife.org/data/taxon/6G4K4

USDA PLANTS Database. (n.d.). Epilobium hornemannii. Retrieved May 5, 2024, from https://plants.usda.gov/home/plantProfile?symbol=EPHO

Uses

no references

Map and Distribution

Global Biodiversity Information Facility (GBIF). (n.d.). Epilobium hornemannii. Retrieved May 5, 2024, from https://www.gbif.org/species/3189153

Plants of the World Online. (n.d.). Epilobium hornemannii. Retrieved May 5, 2024, from https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:611932-1

NatureServe Explorer. (n.d.). Epilobium hornemannii. Retrieved May 5, 2024, from https://explorer.natureserve.org/Taxon/ELEMENT_GLOBAL.2.128233/Epilobium_hornemannii

Description and Information

Flora of North America. (n.d.). Epilobium hornemannii. Retrieved May 5, 2024, from http://floranorthamerica.org/Epilobium_hornemannii

Hultén, E. (1968). Flora of Alaska and Neighboring Territories: A Manual of the Vascular Plants (1st ed.) (pg. 692). Stanford University Press.

Alaska Center for Conservation Science – UAF. (n.d.). Epilobium hornemannii. Retrieved May 5, 2024, from https://ecologicalatlas.uaf.edu/index.php/browse-plant-species/atlas-page/?nps_id=805

E-Flora BC: Electronic Atlas of the Plants of British Columbia. (n.d.). Epilobium hornemannii. Retrieved May 5, 2024, from https://linnet.geog.ubc.ca/Atlas/Atlas.aspx?sciname=Epilobium%20hornemannii&redblue=Both&lifeform=7

Canadian Museum of Nature. (n.d.). Epilobium hornemannii. Retrieved May 5, 2024, from https://nature.ca/aaflora/data/www/onep.htm

 

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