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Achillea millefolium

Achillea millefolium L.

Original Published Description:

Linnaeus (1753).  Species Plantarum. 2,

Common Names

Common yarrow

Languages: English

Overview

General Description

Achillea millefolium was first described by Linnaeus in Species Plantarum in 1853.

A. millefolium is a perennial herb that usually spreads via rhizome.  It is characterized by feathered leaves, proximally petiolate and distally sessile, that gradually reduce in size as they approach the apex of the plant.  The ray flowers can range from white to pink to dark purple, but the disc flowers are always white or grayish white.  It has a variety of ploidy levels, from 2n = 18 to 2n = 72.  Because of its huge degree of variability, it has often been treated as several distinct species or as one species with several varieties.  It has one of the most expansive ranges, growing in virtually every corner of North America.  This may be due to its ability to tolerate meadows and woodlands, dry or damp soils, and to accomodate altitudes from sea level to 3600 m.  In fact, much observable variation in A. millefolium can be contributed to environmental differences. 

Author(s): Hamilton, Hayley
Rights holder(s): Hamilton, Hayley

Conservation

Conservation Status

The morphological variant previously recognized as Achillea Borealis or Achillea millefolium var. Borealis is a species of special concern in Canada.  (USDA, 2010.)  Similarly, the eco-morphotype previously known as A. megacephala or A. millefolifum var. megacephala is of special concern in Canada.  (Trock, 2006.)

Author(s): Hamilton, Hayley
Rights holder(s): Hamilton, Hayley

Management

Although A. millefolium contains alkaloids and other volatile compounds, it is not considered toxic because it is so rarely consumed by livestock.  (US Forest Service, 2010.)

Author(s): Hamilton, Hayley
Rights holder(s): Hamilton, Hayley

Description

Look Alikes

The feathered leaves of Achillea millefolium resemble those of Anthemis cotula (mayweed chamomile), Matricaria discoidea (pineapple weed) and Daucus carota (wild carrot), though all can easily be distinguished by their blooms.  (Calhoun, 2010.)  Conversely, the flowers of A. millefolium are easily confused with those of Lepidium latifolium (perennial pepperweed) and Cardaria draba (hoary cress).  The highly divided leaves of A. millefolium allow for distinction from these look-alikes.  (Donaldson, 2004.)

Author(s): Hamilton, Hayley
Rights holder(s): Hamilton, Hayley

Cytology

The chromosome number of A. millefolium varies, and has been observed as 2n = 18, 27, 36, 45, 54, 63, 72.  (Trock, 2006.)  

Author(s): Hamilton, Hayley
Rights holder(s): Hamilton, Hayley

Genetics

In the Western US, the tetraploid (2n=36) and the hexaploid (2n=54) are the dominant ploidy levels.  (Tyrl, 1969.)  Capable of hybridization between ploidies, A. millefolium has been observed at every ploidy level up to octoploid (2n=72) worldwide.

Author(s): Hamilton, Hayley
Rights holder(s): Hamilton, Hayley

Growth

Achillea millefolium has a moderate growth rate. 

Author(s): Hamilton, Hayley
Rights holder(s): Hamilton, Hayley

Palynology

Achillea millefolium has pollen classified as trizonocolporate, with a lacunate aperture and echinate sculpturing.  (Meo & Khan, 2003.)

Author(s): Hamilton, Hayley
Rights holder(s): Hamilton, Hayley

Ecology and Distribution

Phenology

Achillea millefolium has different flowering periods depending on where it's located.  In the south, it flowers late April to early July, but in the north it doesn't begin flowering until mid-July and will continue through mid-September.  (Trock, 2006.)

Author(s): Hamilton, Hayley
Rights holder(s): Hamilton, Hayley

Associations

Achillea millefolium is a source of nectar for many species of flies, wasps and a few bees.  Some grasshoppers, aphids, beetles and caterpillars may feed on it.

Author(s): Hamilton, Hayley
Rights holder(s): Hamilton, Hayley

Distribution

Achillea millefolium spans the entire continental U.S. (including Alaska) and every Canadian province.

For more information, see the map above provided by Flora of North America.  (Trock, 2006.)

Author(s): Hamilton, Hayley
Rights holder(s): Hamilton, Hayley

Habitat

A. millefolium occupies many diverse habitats, including sunny pastures, meadows and roadsides with dry soils, stream sides and waste grounds with sandy or salty soils, and damp woodlands with clay soils.  (Trock, 2006.)  There is, however, some morphological variation (eco-morphotypes or ecotypes) among the species that is dependent on its habitat. 

Author(s): Hamilton, Hayley
Rights holder(s): Hamilton, Hayley

Life Cycle

Perennial

Author(s): Hamilton, Hayley
Rights holder(s): Hamilton, Hayley

Reproduction

Axillary rhizomes of A. millefolium produce new plants annually at their apices.  Vegetative reproduction occurs when the rhizomes are fragmented.  (Bourdot, Field & White, 1985.)

Author(s): Hamilton, Hayley
Rights holder(s): Hamilton, Hayley

Evolution and Systematics

Evolution

According to a 2008 study, A. millefolium has travelled from Europe and southwest Asia to east Asia, then to North America.  The A. millefolium aggregate has been shaped by cycles of differentiation, hybridization and polyplodization, resulting in the now worldwide expanse of the hexaploid (and other polyploids).  (Guo, Saukel & Ehrendorfer, 2008.)

Author(s): Hamilton, Hayley
Rights holder(s): Hamilton, Hayley

Relevance

Diseases

Achillea millefolium is subject to powdery mildew, root and stem rot. 

Author(s): Hamilton, Hayley
Rights holder(s): Hamilton, Hayley

Uses

Achillea millefolium has a long history of cultural and medicinal uses.  In some eastern cultures it has been used in the mystical practice of divination.  A. millefolium can be distilled to form an oil that possesses known anti-inflammatory and blood-staunching abilities.  It has been used to treat internal bleeding, excessive menstrual bleeding, high blood pressure, fever reduction and more.  The leaves have been used, both fresh and dry, as a garnish and in salads.  (Morgenstern, 2010.)

Author(s): Hamilton, Hayley
Rights holder(s): Hamilton, Hayley

Taxonomy

  • Achillea albida Willd. (synonym)
  • Achillea alpicola (Rydb.) Rydb. (synonym)
  • Achillea ambigua Boiss. (synonym)
  • Achillea ambigua Pollini (synonym)
  • Achillea anethifolia Fisch. ex Herder (synonym)
  • Achillea angustissima Rydb. (synonym)
  • Achillea arenicola A. Heller (synonym)
  • Achillea bicolor Wender. (synonym)
  • Achillea californica Pollard (synonym)
  • Achillea ceretanica Sennen (synonym)
  • Achillea compacta Lam. (synonym)
  • Achillea coronopifolia Willd. (synonym)
  • Achillea crassifolia Colla (synonym)
  • Achillea cristata Hort. ex DC. (synonym)
  • Achillea cuspidata Wall. (synonym)
  • Achillea dentifera Rchb. (synonym)
  • Achillea eradiata Piper (synonym)
  • Achillea fusca Rydb. (synonym)
  • Achillea gigantea Pollard (synonym)
  • Achillea gracilis Raf. (synonym)
  • Achillea haenkeana Tausch (synonym)
  • Achillea intermedia Schleich. (synonym)
  • Achillea lanata Lam. (synonym)
  • Achillea laxiflora A.Nelson (synonym)
  • Achillea laxiflora Pollard & Cockerell (synonym)
  • Achillea magna All. (synonym)
  • Achillea magna Haenke (synonym)
  • Achillea magna L. (synonym)
  • Achillea marginata Turcz. ex Ledeb. (synonym)
  • Achillea megacephala Raup (synonym)
  • Achillea nabelekii Heimerl (synonym)
  • Achillea nigrescens (E. Mey.) Rydb. (synonym)
  • Achillea occidentalis (DC.) Raf. ex Rydb. (synonym)
  • Achillea ochroleuca Eichw. (synonym)
  • Achillea ossica K.Koch (synonym)
  • Achillea palmeri Rydb. (synonym)
  • Achillea pannonica Scheele (synonym)
  • Achillea pecten-veneris Pollard (synonym)
  • Achillea pratensis Saukel & R. Länger (synonym)
  • Achillea pseudotanitifolia Wierzb. ex Rchb. (synonym)
  • Achillea puberula Rydb. (synonym)
  • Achillea pumila Schur (synonym)
  • Achillea rosea Desf. (synonym)
  • Achillea seidlii J.Presl & C.Presl (synonym)
  • Achillea setacea Schwein. (synonym)
  • Achillea sordida (W.D.J.Koch) Dalla Torre & Sarnth. (synonym)
  • Achillea subalpina Greene (synonym)
  • Achillea subhirsuta Gilib. (synonym)
  • Achillea submillefolium (synonym)
  • Achillea sylvatica Becker (synonym)
  • Achillea tanacetifolia Mill. (synonym)
  • Achillea tenuifolia Salisb. (synonym)
  • Achillea tenuis Schur (synonym)
  • Achillea tomentosa Pursh (synonym)
  • Achillea virgata Hort. ex DC. (synonym)
  • Achillios millefoliatus St.-Lag. (synonym)
  • Alitubus millefolium (L.) Dulac (synonym)
  • Alitubus tomentosus Dulac (synonym)
  • Chamaemelum millefolium (L.) E.H.L. Krause (synonym)
  • Chamaemelum tanacetifolium (All.) E.H.L.Krause (synonym)
  • Chamaemelum tomentosum (L.) E.H.L.Krause (synonym)

References

Bourdot, G. W., Field R. J., & White J. G. H. (1985).  Growth Analysis of Achillea millefolium L. (Yarrow) in the Presence and Absence of a Competitor-Hordeum vulgare L. (Barley). New Phytologist. 101(3), 507-519.
Calhoun, R. (2010).  MSU Turf Weeds.net.
Donaldson, S. (2004).  Invasive Weeds of the Lake Tahoe Basin.
Guo, Y-P., Saukel J., & Ehrendorfer F. (2008).  AFLP trees versus scatterplots: evolution and phylogeography of the polyploid complex Achillea millefolium agg. (Asteraceae). Taxon. 57(1), 153-169.
Linnaeus (1753).  Species Plantarum. 2,
Meo, A A., & Khan M A. (2003).  Pollen morphology of Achillea (Compositae-Anthemoideae) Species from Pakistan. Pakistan Journal of Weed Science. 9(3 & 4), 253-258.
Morgenstern, K. (2010).  Herb Profile Yarrow. Sacred Earth Ethnobotany & Ecotravel. 2010,
Service, US F. (2010).  Species: Achillea millefolium.
Trock, D. K. (2006).  Achillea. (Editorial Committee of Flora of North America, Ed.).19, 492-494. New York, NY: Oxford University Press.
Tyrl, R. J. (1969).  Cytogeography of Achillea Millefolium in Western Oregon. Brittonia. 21(3), 215-223.
USDA, NRCS. (2010).  The PLANTS Database.