Helianthus tuberosus |
Helianthus gracilentus |
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|---|---|---|
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girasole, hélianthe scrofuleux, Jerusalem artichoke, Jerusalem sunflower, rough sunflower, topinambour, tuberous sunflower |
slender sunflower, whiteleaf sunflower |
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| Habit | Perennials, 50–200+ cm (rhizomatous, producing tubers late in growing season). | Perennials, 60–200 cm (taprooted). |
| Stems | erect, scabro-hispid to hirsute (sometimes glaucous). |
(reddish or purplish) erect, hairy. |
| Leaves | mostly cauline; opposite or alternate proximally, usually alternate distally; petioles 2–8 cm (often ± winged); blades (3-nerved from near bases) lanceolate to ovate, 10–23 × 7–15 cm, bases broadly to narrowly cuneate, margins entire or serrate (flat), abaxial faces puberulent or hirsutulous to tomentulose and gland-dotted (abaxial) or ± scabrous (adaxial). |
cauline; all or mostly opposite; petioles 0–3 cm; blades (1- or 3-nerved) lanceolate to lance-ovate, 5–11 × 2–3.5 cm, bases cuneate, margins entire or serrate, abaxial faces hispid, gland-dotted. |
| Peduncles | 1–15 cm. |
2.5–30 cm. |
| Involucres | hemispheric, (10–25 ×) 8–12 mm. |
hemispheric, 13–20 mm diam. |
| Ray florets | 10–20; laminae 25–40 mm. |
13–21; laminae 15–25 mm (abaxial faces gland-dotted). |
| Disc florets | 60+; corollas 6–7 mm, lobes yellow; anthers dark brown or black, appendages dark or yellowish. |
50+; corollas 5–6 mm, lobes reddish; anthers reddish brown, appendages yellow or dull orange (style branches yellow). |
| Phyllaries | (often dark green, drying nearly black) 22–35 (bases appressed, apices ± spreading, sometimes reflexed in fruit), lanceolate, 8.5–15 × 2–4 mm (subequal), (margins ciliate) apices acuminate, abaxial faces hispidulous or puberulent, gland-dotted. |
20–25, lanceolate, 4–8 × 1.5–3 mm, (margins ciliate) apices acute, abaxial faces hispidulous, gland-dotted. |
| Heads | 3–15. |
1–5. |
| Cypselae | 5–7 mm, glabrous or distally hairy; pappi of 2 aristate scales 1.9–3 mm plus 0–1 deltate scales 0.5–0.8 mm. |
3–4 mm, glabrate; pappi of 2 aristate scales 2.5–3 mm. |
| Paleae | 8–9 mm, 3-toothed (apices hairy). |
8–9 mm, subentire to weakly 3-toothed (apices acute, ciliate, gland-dotted). |
| 2n | = 102. |
= 34. |
Helianthus tuberosus |
Helianthus gracilentus |
|
| Phenology | Flowering late summer–fall. | Flowering late spring–fall. |
| Habitat | Roadsides, fields, waste areas | Dry slopes |
| Elevation | 0–1000(–1500) m [0–3300(–4900) ft] | 0–1800 m [0–5900 ft] |
| Distribution |
AL; AR; CO; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; NC; ND; NE; NH; NJ; NY; OH; OK; PA; RI; SC; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; MB; NB; NS; ON; PE; QC; SK; cultivated and adventive in Europe
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CA; Mexico (Baja California)
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| Discussion | Helianthus tuberosus is variable, probably in part stemming from hybridization with other polyploids, including H. pauciflorus, H. resinosus, and H. strumosus. Helianthus tuberosus is so widely spread as a weedy species that its original distribution is difficult to discern. It has been used as a food plant for its tubers by native Americans (although not necessarily domesticated or even cultivated); it has been developed as a crop primarily in Europe, where it has become widely naturalized. The common name Jerusalem artichoke is a misnomer, as explained by C. B. Heiser (1976). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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| Parent taxa | ||
| Sibling taxa | ||
| Synonyms | H. tomentosus, H. tuberosus var. subcanescens | |
| Name authority | Linnaeus: Sp. Pl. 2: 905. (1753) | A. Gray: Proc. Amer. Acad. Arts 11: 77. (1876) |
| Source | FNA vol. 21, p. 161. | FNA vol. 21, p. 168. |
| Web links |
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