Volume 13 > Part 2 > Year 2016 > Page 324 > Compositae (Asteraceae) > Helianthus

1. Helianthus annuus L.wfo-0000088131

Sp. Pl. 2: 904. 1753; Backer & Bakh.f., Fl. Java 1: 406. 1965; Chen, Fl. Reipubl. Popularis Sin. 75: 358. 1979; Y.S.Chen & D.J.N.Hind, Fl. China 20–21: 875. 2011.

Accepted Name : This is currently accepted.

Description : Coarse annual herb from a tap root, 1–3 m tall; stems erect, unbranched and single-headed (in cultivated forms), often branched above, branches ending in inflorescences. Leaves long petiolate; blade ovate, 10–40 by 5–25 cm, apex acuminate, base usually cordate, margins serrate, both surfaces scabrous and glandular-dotted; petioles to 25 cm long. Inflorescences solitary (in cultivated forms), a few capitula in open corymbs; peduncles with solid pith. Capitula radiate, disc 3 cm wide (to 30 cm in cultivated); involucres hemispherical or depressed, 1.5–3 cm long (to 5 cm in cultivated forms), 3–5 cm diam.; phyllaries 3-seriate, imbricate, herbaceous, ovate to ovate-oblong, apex long acuminate, spreading; receptacle flattened, paleaceous, paleae ovate, scarious, apex long acuminate. Ray florets 17–30 or more (–100) per capitulum, neuter; rays yellow, lanceolate, 2.5–8 by 1.6–2 cm. Disc florets many per capitulum, bisexual; corollas 6–8 mm long, apex 5-lobed, lobes yellow. Achenes obovoid, ca 12 mm long, compressed or 4-angled, setuliferous; pappus of 2 lanceolate scales, with smaller ones in between, caducous.

Thailand : NORTHERN: Chiang Mai (cultivated, but now escaped elsewhere); CENTRAL: Saraburi.

Distribution : Native of S America (Peru – type).

Ecology : Cultivated as a garden ornamental or as a food material.

Vernacular : Chon tawan (ชอนตะวัน)(Central); than tawan (ทานตะวัน)(Northern); bua thong (บัวทอง)(Chiang Mai, Northern).

CommonName : Sunflower.