Helianthus maximiliani |
Helianthus annuus |
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hélianthe de maximilien, Maximilian sunflower, Maximilian's sunflower |
common sunflower, hairy leaf sunflower, sunflower |
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Habit | Perennials, 50–300 cm (rhizomatous). | Annuals, 100–300 cm. |
Stems | erect, 5–30 dm, scabrous to scabro-hispidulous. |
erect, usually hispid. |
Leaves | cauline; mostly alternate; petioles 0–2 cm; blades (light green to gray-green, 1-nerved, conduplicate) lanceolate, 10–30 × 2–5.5 cm, bases cuneate, margins usually entire, sometimes serrulate, abaxial faces scabrous to scabro-hispid, gland-dotted. |
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. |
Peduncles | 1–11 cm. |
2–20 cm. |
Involucres | hemispheric, 13–28 mm diam. |
hemispheric or broader, 15–40(–200+) mm diam. |
Ray florets | 10–25; laminae (15–)25–40 mm. |
(13–)17–30(–100+); laminae 25–50 mm. |
Disc florets | 75+; corollas 5–7 mm, lobes yellow; anthers dark brown or black; appendages usually yellow, sometimes partly dark. |
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). |
Phyllaries | 30–40, lanceolate, 14–20 × 2–3 mm, (margins ciliate) apices acute to attenuate, abaxial faces canescent, gland-dotted. |
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. |
Heads | (1–)3–15 (often in racemiform to spiciform arrays). |
1–9. |
Cypselae | 3–4 mm, glabrate; pappi of 2 aristate scales 3–4.1 mm. |
(3–)4–5(–15) mm, glabrate; pappi of 2 lanceolate scales 2–3.5 mm plus 0–4 obtuse scales 0.5–1 mm. |
Paleae | 7–11 mm, entire or 3-toothed (apices greenish, mucronate, hairy). |
9–11 mm, 3-toothed (middle teeth long-acuminate, glabrous or hispid). |
2n | = 34. |
= 34. |
Helianthus maximiliani |
Helianthus annuus |
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Phenology | Flowering late summer–fall. | Flowering summer–fall. |
Habitat | Prairies, fields, waste areas | Open areas |
Elevation | 0–300(–2100+) m (0–1000(–6900+) ft) | 0–3000 m (0–9800 ft) |
Distribution |
AL; AR; CA; CO; CT; DC; DE; IA; ID; IL; IN; KS; KY; MA; MD; ME; MI; MN; MO; MS; NC; ND; NE; NJ; NY; OH; OK; PA; SC; SD; TN; TX; UT; VA; WA; WI; WV; WY; AB; BC; MB; ON; QC; SK; Mexico
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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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Discussion | Helianthus maximiliani is introduced in eastern Ontario and in Quebec. It appears to be native to midcontinental prairie regions and has spread along railroads and highways into all areas of North America. Its wide dispersal may be aided by cultivation for its attractive, showy floral displays. In addition to the usually conduplicate, single-nerved leaves and spikelike arrangement of the heads, it is distinguished by the whitish-canescent indument of the leaves and stems and the long-attenuate phyllaries. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
Source | FNA vol. 21, p. 166. | FNA vol. 21, p. 149. |
Parent taxa | Asteraceae > tribe Heliantheae > subtribe Helianthinae > Helianthus | Asteraceae > tribe Heliantheae > subtribe Helianthinae > Helianthus |
Sibling taxa | ||
Synonyms | H. dalyi | 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 | Schrader: Index Seminum (Göttingen) 1834: unpaged. (1835) | Linnaeus: Sp. Pl. 2: 904. (1753) |
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