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Helianthus annuus

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, Eucephalus, 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; Whitneya in Arnica. Amauriopsis in TJM2 (2012) treated here in Hymenothrix; Arida in Leucosyris; Bahia in Picradeniopsis.
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: HelianthusView DescriptionDichotomous Key

Common Name: SUNFLOWER
Habit: Annual or perennial herb (subshrub). Stem: generally erect. Leaf: opposite or alternate, generally reduced distally on stem, often 3-veined from near base, generally +- flat, generally green, generally rough-hairy. Inflorescence: heads radiate, 1 or in cyme-like clusters; involucre bell-shaped to hemispheric; phyllaries in 1--3 generally +- equal series; receptacle flat to rounded, paleate; paleae 0--3-lobed. Ray Flower: 10--many, sterile; ray yellow. Disk Flower: many; corolla yellow to red or purple, tube short, throat base tapered or often swollen, lobes triangular; style appendages triangular. Fruit: oblanceolate to obovate, +- compressed, sides rounded; pappus generally of 2 deciduous, lanceolate to ovate scales (+ 0--several shorter scales).
Species In Genus: 53 species: America. Etymology: (Greek: sun flower) Note: Helianthus maximilianii Schrad. a garden plant only.
eFlora Treatment Author: David J. Keil

Helianthus annuus L.
Habit: Annual <= 3 m. Stem: +- rough-hairy. Leaf: most alternate; petiole 2--20 cm; blade 10--40 cm, +- widely lanceolate to triangular-ovate, base wedge-shaped to truncate or +- cordate, tip obtuse to acute, margin +- entire to serrate, abaxially bristly, sometimes gland-dotted. Inflorescence: heads generally 1--9; peduncle 2--20 cm; involucre generally 1.5--4 cm diam; phyllaries 13--25 mm, generally 5--8 mm wide, lanceolate to widely ovate, abruptly acuminate, glabrous to rough-hairy, generally ciliate; paleae deeply 3-lobed, middle lobe long-acuminate. Ray Flower: (13)15--30+; ray generally 5--50 mm. Disk Flower: corolla 5--8 mm, throat proximally enlarged, goblet-shaped, lobes red to purple or yellow. Fruit: (3)4--5(15) mm; main pappus scales 2, lanceolate, 2--3.5 mm, smaller scales 0--4, obtuse. Chromosomes: 2n=34.
Ecology: Disturbed areas, scrub, grassland, many other habitats; Elevation: < 2000 m. Bioregional Distribution: CA; Distribution Outside California: to eastern North America. Flowering Time: Jun--Oct Note: Highly variable; hybridizes with several other annual species. Many cultivated forms may be waifs. Robust subshrub from central SNF may be new sp.
Synonyms: Helianthus annuus subsp. jaegeri (Heiser) Heiser; Helianthus annuus subsp. lenticularis (Douglas) Cockerell; Helianthus annuus var. macrocarpus (DC.) Cockerell
eFlora Treatment Author: David J. Keil
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Citation for this treatment: David J. Keil 2017. Helianthus annuus, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on October 22, 2017.

Citation for the whole project: Jepson Flora Project (eds.) 2017. Jepson eFlora,, accessed on October 22, 2017.

Helianthus annuus
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© 2013 Neal Kramer
Helianthus annuus
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© 2012 Neal Kramer
Helianthus annuus
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© 2014 Neal Kramer
Helianthus annuus
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© 2009 Barry Breckling
Helianthus annuus
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© 2002 Tony Morosco
Helianthus annuus
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© 2012 Neal Kramer

More photos of Helianthus annuus in CalPhotos

Geographic subdivisions for Helianthus annuus:
Markers link to CCH specimen records. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues. Purple markers indicate specimens collected from a garden, greenhouse, or other non-wild location.
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).

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Data provided by the participants of the Consortium of California Herbaria.
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CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa.
Blue line denotes eFlora flowering time.