Annuals, 100-300 cm. Stems erect, usually hispid. Leaves mostly cauline, mostly alternate; petiole 2-20 cm; blade ovate-lanceolate to ovate, 10-40 × 5-40 cm, abaxially usually ± hispid, sometimes gland-dotted, base cuneate to subcordate or cordate, margin serrate. Capitula 1-9; peduncles 2-20 cm; involucres hemispheric or broader, 15-40(-200) mm in diam.; phyllaries 20-30(-100), ovate to ovate-lanceolate, 13-25 × (3-)5-8 mm, abaxially usually hirsute to hispid, rarely glabrate or glabrous, usually gland-dotted, margin usually ciliate, apex abruptly narrowed, long acuminate; paleae 9-11 mm, 3-toothed, middle teeth long acuminate, glabrous or hispid. Ray florets (13-)17-30(-100+); lamina 25-50 mm. Disk florets 150-1000; corollas 5-8 mm, throats bulbous at bases, lobes usually reddish, sometimes yellow; anthers brownish to black, appendages yellow or dark. Achenes (3-)4-5(-15) mm, glabrate; pappus of 2 lanceolate scales 2-3.5 mm plus 0-4 obtuse scales 0.5-1 mm. Fl. Jul-Sep, fr. Aug-Oct. 2n = 34.
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.
"Coarse, rough-hairy annual (0.5–)1–3 m; lvs chiefly alternate (except the lowermost), mostly toothed, long-petiolate, ovate or broader, at least the lower cordate in well developed plants; heads large, the red-purple (yellow) disk seldom under 3 cm wide; invol bracts ovate or ovate-oblong and abruptly narrowed above the middle to the acuminate tip, ciliate and with some rather long coarse hairs on the back; receptacle flat or nearly so, its bracts inconspicuously hairy at the tip; 2n=34. A weed in disturbed sites, especially in moist, low ground, throughout the U.S. and adj. Can. and Mex. July–Sept. Typical wild plants are branched, with several or many heads. Cult. forms, which readily escape, have solitary (or few), often much larger heads. (H. lenticularis; H. aridus)"
Sunflower, originally from America, is cultivated in many places in East Africa for its seeds, as an oil crop. Occasionally it seems to escape and become naturalised, as in T 6, Uzaramo District: Dar es Salaam on airport road, Apr. 1977, Wingfield 3392a! and T 8, Songea District: Mkaku River SW of Kitai, Mar. 1956, Milne-Redhead & Taylor 9075!.
These escapes are small annual herbs, 20–120 cm high.
Leaves alternate, ovate, to 8 x 3.5 cm and scabridulous to the touch, petiolate.
In cultivation the plant and all its parts may become much larger. Both the cited specimens came from road-sides.
Capitula terminal and solitary; ray florets ± 14, yellow, 35 x 10 mm; disc florets very many, yellow orange.
0,5–2,5 m hoch, kaum verzweigt, rauhaarig. Blätter wechselständig, herz- bis eiförmig, spitz gezähnt. Blütenköpfe einzeln oder wenige, nickend, Durchmesser 10–40 cm. Zungenblüten 20–70, 6–10 cm lang und bis 2 cm breit, meist gelb. Röhrenb
Annual herb, up to 4 m high; usually branching from base. Leaves alternate, sometimes opposite below; blade ovate to triangular, up to 100 x 60 mm, apex acuminate, base cordate to truncate and abruptly descending on petiole, margins dentate or denticulate, scabrid-pubescent on both surfaces; petiole up to ± 100 mm long. Heads radiate, generally 80-100 mm in diameter, sometimes larger, solitary on long peduncles terminating upper branches. Involucral bracts 3-seriate, ovate, usually > 4 mm wide, mostly abruptly long-acuminate, scabridulous. Receptacle with paleae enfolding disc florets. Flowers: ray florets neuter, yellow; disc florets bisexual, brownish or purplish black; Mar. Fruit with cypsela narrowly obovate, ± 5 mm long, somewhat compressed, thinly hispid. Pappus of 2 small scales, soon caducous.
Annual herb to 4 m, usually branching from the base. Leaves alternate, sometimes opposite below, lamina of upper leaves up to c. 10 x 6 cm, lower leaves often much larger, ovate to triangular, apex acuminate, base cordate to truncate and abruptly descending on the petiole, scabrid-pubescent on both surfaces, petiole up to c. 10 cm long. Heads generally 8-10 cm across the expanded rays but sometimes much larger, solitary on long peduncles terminating the upper branches. Involucral bracts triseriate, ovate-lanceolate, mostly abruptly long-acuminate, scabridulous. Rays yellow, disc brownish- or purplish-black. Achenes c. 5 mm long, narrowly obovate, somewhat compressed, thinly hispid, pappus of 2 small narrow scales, soon caducous.
It sometimes occurs as a ruderal, either the small-headed typical plant described here, well established in sandy waste ground at the head of Durban Bay, or the selected, giant-headed garden and agricultural forms, which are occasionally seen in waste ground near habitation or along roadsides.