Helianthus annuus

Linnaeus
Sp. Pl. 2: 904. 1753.
Common names: Common sunflower
Illustrated
Synonyms: Helianthus annuus subsp. jaegeri (Heiser) Heiser Helianthus annuus subsp. lenticularis (Douglas ex Lindley) Cockerell Helianthus annuus var. lenticularis (Douglas ex Lindley) Steyermark Helianthus annuus var. macrocarpus (de Candolle) Cockerell Helianthus annuus subsp. texanus Heiser Helianthus aridus Helianthus jaegeri Helianthus lenticularis Helianthus macrocarpus
Treatment appears in FNA Volume 21. Treatment on page 149. Mentioned on page 142, 145, 150, 153, 154, 1.

Annuals, 100–300 cm. Stems erect, usually hispid. 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. Heads 1–9. Peduncles 2–20 cm. Involucres hemispheric or broader, 15–40(–200+) mm diam. 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. Paleae 9–11 mm, 3-toothed (middle teeth long-acuminate, glabrous or hispid). Ray florets (13–)17–30(–100+); laminae 25–50 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). 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. 2n = 34.


Phenology: Flowering summer–fall.
Habitat: Open areas
Elevation: 0–3000 m

Distribution

V21-345-distribution-map.gif

St. Pierre and Miquelon, Alta., B.C., Man., N.B., N.W.T., N.S., Ont., P.E.I., Que., Sask., Ala., Ariz., Ark., Calif., Colo., Conn., Del., D.C., Fla., Ga., Idaho, Ill., Ind., Iowa, Kans., Ky., La., Maine, Md., Mass., Mich., Minn., Miss., Mo., Mont., Nebr., Nev., N.H., N.J., N.Mex., N.Y., N.C., N.Dak., Ohio, Okla., Oreg., Pa., R.I., S.C., S.Dak., Tenn., Tex., Utah, Vt., Va., Wash., W.Va., Wis., Wyo., Mexico, intoduced nearly worldwide.

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.

Selected References

None.

Lower Taxa

None.

... more about "Helianthus annuus"
Edward E. Schilling +
Linnaeus +
Common sunflower +
St. Pierre and Miquelon +, Alta. +, B.C. +, Man. +, N.B. +, N.W.T. +, N.S. +, Ont. +, P.E.I. +, Que. +, Sask. +, Ala. +, Ariz. +, Ark. +, Calif. +, Colo. +, Conn. +, Del. +, D.C. +, Fla. +, Ga. +, Idaho +, Ill. +, Ind. +, Iowa +, Kans. +, Ky. +, La. +, Maine +, Md. +, Mass. +, Mich. +, Minn. +, Miss. +, Mo. +, Mont. +, Nebr. +, Nev. +, N.H. +, N.J. +, N.Mex. +, N.Y. +, N.C. +, N.Dak. +, Ohio +, Okla. +, Oreg. +, Pa. +, R.I. +, S.C. +, S.Dak. +, Tenn. +, Tex. +, Utah +, Vt. +, Va. +, Wash. +, W.Va. +, Wis. +, Wyo. +, Mexico +  and intoduced nearly worldwide. +
0–3000 m +
Open areas +
Flowering summer–fall. +
Illustrated +
Helianthus annuus subsp. jaegeri +, Helianthus annuus subsp. lenticularis +, Helianthus annuus var. lenticularis +, Helianthus annuus var. macrocarpus +, Helianthus annuus subsp. texanus +, Helianthus aridus +, Helianthus jaegeri +, Helianthus lenticularis +  and Helianthus macrocarpus +
Helianthus annuus +
Helianthus +
species +