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Achillea millefolium

Higher Taxonomy
Family: Asteraceae (Compositae)View DescriptionDichotomous Key
Habit: Annual to tree. Leaf: basal and/or cauline, alternate, opposite, rarely whorled, simple to 2+ × compound. Inflorescence: 1° inflorescence a head, resembling a flower, of several types (see below), 1--many in generally +- cyme-like cluster; each head generally with +- calyx-like involucre of 1--many series of phyllaries (involucre bracts); receptacle of head flat to conic or columnar, paleate (bearing paleae = receptacle bracts) or epaleate; flowers 1--many per head. Flower: bisexual, unisexual, or sterile, +- small, of several types (see below); calyx 0 or modified into +- persistent pappus of bristles, scales, and/or awns; corolla radial or bilateral (0), lobes generally (0)3--5; stamens 4--5, filaments generally free, generally fused to corolla at tube/throat junction, anthers generally fused into cylinder around style, anther base generally rounded or cordate (deeply sagittate or with tail-like appendages), tip (= flattened appendage) generally projecting beyond pollen sac; pistil 1, 2-carpeled, ovary inferior, 1-chambered, 1-seeded, placenta basal, style 1, tip generally +- 2-branched (except in some staminate disk flowers), branch tips truncate or generally bearing +- brush-like appendages; stigmas 2, generally on adaxial faces of style branches. Fruit: achene (also called a cypsela) (drupe in Chrysanthemoides), cylindric to ovoid, sometimes compressed, generally deciduous with pappus attached.
Genera In Family: +- 1500 genera, 23000 species: worldwide, many habitats. Note: Flower and head types differ in form and sexual condition. A disk flower has a generally radial corolla, with a cylindric tube, expanded throat, and generally 5 lobes. Disk flowers are generally bisexual and fertile but occasionally staminate with reduced ovaries. Discoid heads comprise only disk flowers. A radiant head is a variant of a discoid head, with peripheral disk flower corollas expanded, often bilateral. A ray flower corolla is bilateral, generally with a slender tube and flattened petal-like ray (single lip composed of generally 3 lobes). Ray flowers are generally pistillate or sterile (occasionally lacking styles). Radiate heads have peripheral ray flowers and central disk flowers. Disciform heads superficially resemble discoid heads, with pistillate or sterile flowers that lack rays, together with or separate from disk flowers. A ligulate flower is bisexual, with a bilateral, generally ephemeral corolla and 5-lobed ligule. Liguliflorous heads comprise only ligulate flowers. See glossary p. 31 for illustrations of family characteristics. Echinops sphaerocephalus L., Gaillardia aristata Pursh, Gaillardia pulchella Foug., Hymenothrix loomisii S.F. Blake, Tagetes erecta L., Thelesperma megapotamicum (Spreng.) Kuntze are waifs. Melampodium perfoliatum Kunth, historic urban waif. Ageratum conyzoides L., Guizotia abyssinica (L. f.) Cass., Santolina chamaecyparisus L., orth. var. are rare or uncommon escapes from cultivation. Dyssodia papposa, Ismelia carinata (Schousb.) Sch. Bip. [Chrysanthemum carinatum Schousb.], Mantisalca salmantica (L.) Briq. & Cavill. are historical or extirpated waifs in California. Inula helenium L. not documented in California. Taxa of Aster in TJM (1993) treated here in Almutaster, Doellingeria, Eurybia, Ionactis, Oreostemma, Sericocarpus, Symphyotrichum; Chamomilla in Matricaria; Bahia in Hymenothrix; Cnicus in Centaurea; Conyza in Erigeron and Laennecia; Dugaldia in Hymenoxys; Erechtites in Senecio; Hymenoclea in Ambrosia; Lembertia in Monolopia; Osteospermum ecklonis in Dimorphotheca; Picris echioides in Helminthotheca; Prionopsis in Grindelia; Raillardiopsis in Anisocarpus and Carlquistia; Schkuhria multiflora in Picradeniopsis; Trimorpha in Erigeron; Venidium in Arctotis; Viguiera in Aldama and Bahiopsis; Whitneya in Arnica. Amauriopsis in TJM2 (2012) treated here in Hymenothrix; Arida in Leucosyris; Bahia in Picradeniopsis; Eucephalus in Doellingeria.
Unabridged Note: Largest family of vascular plants in California and of eudicots globally.
eFlora Treatment Author: David J. Keil, except as noted
Scientific Editor: David J. Keil, Bruce G. Baldwin.
Genus: AchilleaView Description 

Common Name: YARROW
Habit: Perennial herb, strongly scented. Leaf: [simple to] 3-pinnately dissected, basal and cauline, alternate, +- reduced distally on stem, +- hairy. Inflorescence: heads radiate, many, small, in generally flat-topped clusters; involucre bell-shaped or ovoid; phyllaries graduated in 3--4 series, ovate, obtuse; margins membranous; receptacle flat to rounded, paleate; paleae narrow, transparent, +- folded. Ray Flower: (3)5--8; ray short, generally round, white or pink [yellow]. Disk Flower: +- many; corolla short, white to purple [yellow]. Fruit: oblong to obovate, compressed, thick-margined, glabrous; pappus 0.
Etymology: (Greek: Achilles of ancient mythology)
eFlora Treatment Author: David J. Keil
Reference: Trock 2006 FNANM 19:492--494
Unabridged Reference: Ramsey et al. 2008 Evolution 62:639--653
Achillea millefolium L.
Habit: Plant 10--200 cm. Leaf: finely 3-pinnately divided; cauline leaves +- clasping. Inflorescence: phyllaries 4--9 mm. Ray Flower: ray 2.5--4 mm, ovate to round, white to pink. Disk Flower: 15--40; corolla 2--3 mm, white to pink. Fruit: +- 2 mm. Chromosomes: 2n=[18,27],36,45,54,[63,72].
Ecology: Many habitats; Elevation: < 3650 m. Bioregional Distribution: CA-FP, GB; Distribution Outside California: circumboreal. Flowering Time: Apr--Sep Note: Highly variable polyploid complex; leaf size and hairiness especially variable.
Synonyms: Achillea borealis Bong. subsp. arenicola (A. Heller) D.D. Keck; Achillea lanulosa Nutt. subsp. alpicola (Rydb.) D.D. Keck; Achillea borealis subsp. californica (Pollard) D.D. Keck; Achillea millefolium subsp. lanulosa (Nutt.) Piper; Achillea millefolium var. alpicola (Rydb.) Garrett; Achillea millefolium var. arenicola (A. Heller) Nobs; Achillea millefolium var. borealis (Bong.) Farwell; Achillea millefolium var. californica (Pollard) Jeps.; Achillea millefolium var. gigantea (Pollard) Nobs; Achillea lanulosa var. lanulosa (Nutt.) Piper; Achillea millefolium var. littoralis Nobs; Achillea millefolium var. pacifica (Rydb.) G.N. Jones; Achillea millefolium var. puberula (Rydb.) Nobs
Jepson eFlora Author: David J. Keil
Reference: Trock 2006 FNANM 19:492--494
Index of California Plant Names (ICPN; linked via the Jepson Online Interchange)

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Botanical illustration including Achillea millefolium

botanical illustration including Achillea millefolium

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Citation for this treatment: David J. Keil 2012, Achillea millefolium, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on May 26, 2024.

Citation for the whole project: Jepson Flora Project (eds.) 2024, Jepson eFlora,, accessed on May 26, 2024.

Achillea millefolium  
var. occidentalis
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©2001 Gary A. Monroe
Achillea millefolium
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©2001 Tony Morosco
Achillea millefolium
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©2009 George W. Hartwell
Achillea millefolium
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©2004 George W. Hartwell
Achillea millefolium
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©2008 Keir Morse

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Geographic subdivisions for Achillea millefolium:
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map of distribution 1
(Note: any qualifiers in the taxon distribution description, such as 'northern', 'southern', 'adjacent' etc., are not reflected in the map above, and in some cases indication of a taxon in a subdivision is based on a single collection or author-verified occurence).


Data provided by the participants of the  Consortium of California Herbaria.
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Blue markers indicate specimens that map to one of the expected Jepson geographic subdivisions (see left map). Purple markers indicate specimens collected from a garden, greenhouse, or other non-wild location.
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CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa, if there are more than 1 infraspecific taxon in CA.
Blue line denotes eFlora flowering time (fruiting time in some monocot genera).