Helianthus tuberosus |
Helianthus agrestis |
|
|---|---|---|
|
girasole, hélianthe scrofuleux, Jerusalem artichoke, Jerusalem sunflower, rough sunflower, topinambour, tuberous sunflower |
hélianthe à belles fleurs, southeastern sunflower |
|
| Habit | Perennials, 50–200+ cm (rhizomatous, producing tubers late in growing season). | Annuals, 100(–200+) cm. |
| Stems | erect, scabro-hispid to hirsute (sometimes glaucous). |
erect, glabrous or glabrate (glaucous). |
| 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). |
mostly cauline; mostly opposite; petioles 0.5–1.2 cm; blades (often 3-nerved distal to bases) lanceolate, 6–11 × 0.7–1.9 cm, bases cuneate, margins ± serrate, faces scabrous, not gland-dotted. |
| Peduncles | 1–15 cm. |
2–8 cm. |
| Involucres | hemispheric, (10–25 ×) 8–12 mm. |
hemispheric, 10–15 mm diam. |
| Ray florets | 10–20; laminae 25–40 mm. |
ca. 12; laminae 12–25 mm. |
| Disc florets | 60+; corollas 6–7 mm, lobes yellow; anthers dark brown or black, appendages dark or yellowish. |
50+; corollas 3.5–4 mm, lobes reddish purple; anthers dark, appendages dark. |
| 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. |
15–25, lanceolate, 8–9 × 1.5–2 mm, (margins ciliate) apices acuminate, abaxial faces glabrate. |
| Heads | 3–15. |
1–15. |
| 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. |
2.5–3.2 mm, glabrous (± tuberculate); pappi of 2 aristate scales 1.5–2 mm. |
| Paleae | 8–9 mm, 3-toothed (apices hairy). |
5–7, subentire to ± 3-toothed (apices purplish, glabrous). |
| 2n | = 102. |
= 34. |
Helianthus tuberosus |
Helianthus agrestis |
|
| Phenology | Flowering late summer–fall. | Flowering late summer to fall. |
| Habitat | Roadsides, fields, waste areas | Mucky wet soils, marshes, pine flatwoods |
| Elevation | 0–1000(–1500) m [0–3300(–4900) ft] | 0–50+ m [0–160+ 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
|
FL; GA |
| 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.) |
Distinctive among species of Helianthus with an annual habit in having a combination of reddish disc corolla lobes and yellow style branches, H. agrestis is also characterized by its glabrate stems and phyllaries and by relatively long hairs on the petioles and basal margins of the leaves. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
| Parent taxa | ||
| Sibling taxa | ||
| Synonyms | H. tomentosus, H. tuberosus var. subcanescens | |
| Name authority | Linnaeus: Sp. Pl. 2: 905. (1753) | Pollard: Proc. Biol. Soc. Wash. 13: 184. (1900) |
| Source | FNA vol. 21, p. 161. | FNA vol. 21, p. 148. |
| Web links |
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