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Key to families | Table of families and genera

Specimen numbers are hyperlinked to records in the Consortium of California Herbaria data view where possible. Taxa are hyperlinked to entries in the Jepson Interchange via the "[Online Interchange]" link.


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).
53 species: America. (Greek: sun flower) [Schilling 2006 FNANM 21:141–169] Helianthus maximilianii Schrad. a garden plant only.
Unabridged references: [Heiser et al. 1969 Mem Torrey Bot Club 22(3):1–218]

Key to Helianthus

1. Annual (or robust subshrub)

2. Phyllaries generally 5–8 mm wide, abruptly acuminate ..... H. annuus

2' Phyllaries generally 1–5 mm wide, acute or gradually acuminate

3. Central paleae tipped with stiff white hairs ..... H. petiolaris

4. Leaves and phyllaries densely gray-canescent; corolla throat gradually narrowed distally to slightly hairy basal bulge ..... subsp. canescens

4' Leaves and phyllaries strigose, green; corolla throat abruptly narrowed distally to densely hairy basal bulge ..... subsp. petiolaris

3' Central paleae glabrous or finely appressed-hairy

5. Paleae acute, = or slightly > disk flowers, glabrous or finely appressed-hairy; leaves densely white-hairy ..... H. niveus subsp. tephrodes (2)

5' Paleae awn-tipped, >> disk flowers, tip glabrous; leaves green

6. Leaf blade narrowly lance-ovate to ovate, generally serrate; involucre of larger heads generally 20+ mm diam; fruit 3.5–4.5 mm ..... H. bolanderi

6' Leaf blade lance-linear lance-ovate, generally entire or ± entire (shallowly serrate); involucre of larger heads 15–20 mm diam; fruit 2.7–3.5 mm ..... H. exilis

1' Perennial herb (occasionally flowering in 1st year)

7. Disk corolla lobes red to purple

8. Leaves blue-green, glabrous to sparsely short-rough-hairy or bristly, margins often crinkled; roots horizontal, rhizome-like; ray generally 8–9 mm ..... H. ciliaris

8' Leaves green or densely canescent, margins generally flat; plant taprooted; ray generally >> 1 cm

9. Leaves green, short-rough-hairy or bristly; phyllaries <= disk ..... H. gracilentus (2)

9' Leaves densely white-hairy; phyllaries = or slightly > disk ..... H. niveus subsp. tephrodes (2)

7' Disk corolla lobes yellow

10. Phyllaries <= disk, obtuse to acute ..... H. gracilentus (2)

10' Phyllaries >= disk, generally acuminate

11. Phyllaries generally 12–18; most leaves opposite, generally < 12 cm; plant from taproot ..... H. cusickii

11' Phyllaries generally > 25; most or all leaves alternate, often > 15 cm; plant from rhizome

12. Phyllaries generally 3–5 mm wide, tips of outer generally reflexed at maturity ..... H. californicus

12' Phyllaries generally < 3 mm wide, tips ± erect to reflexed at maturity

13. Phyllaries generally 2–3 mm wide, tips generally spreading to reflexed ..... H. inexpectatus

13' Phyllaries generally 1–1.5 mm wide, tips of outer ± spreading to erect ..... H. nuttallii

14. Phyllaries glabrous or strigose; leaves abaxially short-rough-hairy ..... subsp. nuttallii

14' Phyllaries densely hairy; leaves abaxially ± finely tomentose ..... subsp. parishii


Citation for the whole project: Jepson Flora Project (eds.) [year] Jepson eFlora, [accessed on month, day, year]
Citation for an individual treatment: [Author of taxon treatment] [year]. [Taxon name] in Jepson Flora Project (eds.) Jepson eFlora, [URL for treatment]. Accessed on [month, day, year].
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