Helianthus maximiliani |
Helianthus petiolaris |
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hélianthe de maximilien, Maximilian sunflower, Maximilian's sunflower |
prairie sunflower, unknown |
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Habit | Perennials, 50–300 cm (rhizomatous). | Annuals, 40–200 cm. | ||||
Stems | erect, 5–30 dm, scabrous to scabro-hispidulous. |
erect, usually densely canescent, hispid, or strigillose, rarely ± hirsute or glabrate. |
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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 2–4 cm; blades (often bluish green) lanceolate to deltate-ovate or ovate, 4–15 × 1–8 cm, bases subcordate or truncate to cuneate, margins entire or ± serrate, abaxial faces strigose, sparsely to densely, or not at all, gland-dotted. |
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Peduncles | 1–11 cm. |
4–15(–40) cm. |
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Involucres | hemispheric, 13–28 mm diam. |
± hemispheric, 10–24 mm diam. |
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Ray florets | 10–25; laminae (15–)25–40 mm. |
10–30; laminae 15–20 mm. |
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Disc florets | 75+; corollas 5–7 mm, lobes yellow; anthers dark brown or black; appendages usually yellow, sometimes partly dark. |
50–100+; corollas 4.5–6 mm, lobes usually reddish, rarely yellow; anthers reddish to purplish, appendages purplish (style branches reddish). |
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Phyllaries | 30–40, lanceolate, 14–20 × 2–3 mm, (margins ciliate) apices acute to attenuate, abaxial faces canescent, gland-dotted. |
14–25, lance-linear to lanceolate to lance-ovate, 10–14 × 1–4(–5) mm, (margins sometimes ciliate) apices short-attenuate, abaxial faces usually hispidulous, rarely sparsely hirsute to glabrate. |
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Heads | (1–)3–15 (often in racemiform to spiciform arrays). |
1–5. |
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Cypselae | 3–4 mm, glabrate; pappi of 2 aristate scales 3–4.1 mm. |
3–4.5 mm, ± villous; pappi of 2 aristate scales 1.5–3 mm plus 0–2 erose scales 0.3–0.5 mm. |
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Paleae | 7–11 mm, entire or 3-toothed (apices greenish, mucronate, hairy). |
4.5–7.5 mm, 3-toothed, middle teeth ± ciliate or bearded, hairs whitish, 0.5–0.7 mm. |
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2n | = 34. |
= 34. |
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Helianthus maximiliani |
Helianthus petiolaris |
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Phenology | Flowering late summer–fall. | |||||
Habitat | Prairies, fields, waste areas | |||||
Elevation | 0–300(–2100+) m (0–1000(–6900+) 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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AR; AZ; CA; CO; CT; DC; DE; IA; ID; IL; IN; KS; LA; MA; ME; MI; MN; MO; MT; NC; ND; NE; NJ; NM; NV; NY; OH; OK; OR; PA; SC; SD; TN; TX; UT; VA; WA; WI; WV; WY; AB; MB; ON; SK
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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.) |
Subspecies 2 (2 in the flora). Helianthus petiolaris is adventive beyond western North America. A third subspecies has yet to be named at that rank in Helianthus petiolaris; it has been called H. petiolaris var. canescens A. Gray. It differs in having stems, leaves, and phyllaries densely canescent and abaxial faces of leaves densely gland-dotted. It is additionally characterized by peduncles usually ebracteate, phyllaries 1–2 mm wide, disc corolla throats gradually narrowed distal to slight, not densely hairy basal bulges, and 2n = 34. It flowers late spring through late summer and grows on sandy soils in open areas at (10–)1000–2300 m in Arizona, California, Nevada, New Mexico, and Texas and in Mexico. It was treated as H. niveus (Bentham) Brandegee subsp. canescens (A. Gray) Heiser by C. B. Heiser et al. (1969); molecular and morphologic data appear to favor a placement within H. petiolaris. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 21, p. 166. | FNA vol. 21, p. 152. | ||||
Parent taxa | Asteraceae > tribe Heliantheae > subtribe Helianthinae > Helianthus | Asteraceae > tribe Heliantheae > subtribe Helianthinae > Helianthus | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | H. dalyi | |||||
Name authority | Schrader: Index Seminum (Göttingen) 1834: unpaged. (1835) | Nuttall: J. Acad. Nat. Sci. Philadelphia 2: 115. (1821) | ||||
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