Helianthus annuus |
Helianthus californicus |
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common sunflower, hairy leaf sunflower, sunflower |
California sunflower |
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Habit | Annuals, 100–300 cm. | Perennials, 150–350 cm (rhizomatous). |
Stems | erect, usually hispid. |
erect, glabrous (glaucous). |
Leaves | mostly cauline; mostly alternate; petioles 2–20 cm; blades lance-ovate to ovate, 10–40 × 5–40 cm, bases cuneate to subcordate or cordate, margins serrate, abaxial faces usually ± hispid, sometimes gland-dotted. |
mostly cauline; mostly alternate; petioles 0–3 cm; blades (light to dark green, 3-nerved distal to bases), lanceolate, 10–20 × 2.5–6 cm, bases ± cuneate, margins entire or subentire, abaxial faces hispid to hirsute, gland-dotted. |
Peduncles | 2–20 cm. |
(1–)3–15 cm (gland-dotted). |
Involucres | hemispheric or broader, 15–40(–200+) mm diam. |
broadly hemispheric, 10–25 mm diam. |
Ray florets | (13–)17–30(–100+); laminae 25–50 mm. |
12–21; laminae 15–30 mm. |
Disc florets | 150+(–1000+); corollas 5–8 mm (throats ± bulbous at bases), lobes usually reddish, sometimes yellow; anthers brownish to black, appendages yellow or dark (style branches yellow). |
50+; corollas 6–8 mm, lobes yellow; anthers reddish to dark, appendages reddish brown. |
Phyllaries | 20–30(–100+), ovate to lance-ovate, 13–25 × (3–)5–8 mm, (margins usually ciliate) apices abruptly narrowed, long-acuminate, abaxial faces usually hirsute to hispid, rarely glabrate or glabrous, usually gland-dotted. |
25–35 (loose), lanceolate, 8–15 × 3–5 mm (notably surpassing discs), (margins sometimes ciliate) apices acute to attenuate, abaxial faces hispidulous to glabrate, gland-dotted. |
Heads | 1–9. |
3–10. |
Cypselae | (3–)4–5(–15) mm, glabrate; pappi of 2 lanceolate scales 2–3.5 mm plus 0–4 obtuse scales 0.5–1 mm. |
4.5–5 mm, glabrate; pappi of 2 aristate scales 3–4 mm. |
Paleae | 9–11 mm, 3-toothed (middle teeth long-acuminate, glabrous or hispid). |
10–11 mm, 3-toothed (apices acute, hispidulous). |
2n | = 34. |
= 102. |
Helianthus annuus |
Helianthus californicus |
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Phenology | Flowering summer–fall. | Flowering summer–fall. |
Habitat | Open areas | Stream banks, wet meadows, freshwater marshes |
Elevation | 0–3000 m [0–9800 ft] | 0–1600 m [0–5200 ft] |
Distribution |
AL; AR; AZ; CA; CO; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; AB; BC; MB; NB; NS; NT; ON; PE; QC; SK; SPM; Mexico; intoduced nearly worldwide
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CA; Mexico (Baja California)
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Discussion | Helianthus annuus is widely distributed, including weedy, cultivated, and escaped plants. It is the only native North American species to become a major agronomic crop. Despite its considerable variability, attempts have failed to produce a widely adopted infraspecific system of classification. Forms with red-colored ray laminae, known from cultivation and occasionally seen escaped, trace their ancestry to a single original mutant plant. It hybridizes with many of the other annual species. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 21, p. 149. | FNA vol. 21, p. 167. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | H. annuus subsp. jaegeri, H. annuus subsp. lenticularis, H. annuus var. lenticularis, H. annuus var. macrocarpus, H. annuus subsp. texanus, H. aridus, H. jaegeri, H. lenticularis, H. macrocarpus | |
Name authority | Linnaeus: Sp. Pl. 2: 904. (1753) | de Candolle: in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 5: 589. (1836) |
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