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girasole, hélianthe scrofuleux, Jerusalem artichoke, Jerusalem sunflower, rough sunflower, topinambour, tuberous sunflower

slender sunflower, whiteleaf sunflower

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
map from FNA
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
[WildflowerSearch map]
[BONAP county map]
map from FNA
CA; Mexico (Baja California)
[WildflowerSearch map]
[BONAP county map]
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.)

Parent taxa Asteraceae > tribe Heliantheae > subtribe Helianthinae > Helianthus Asteraceae > tribe Heliantheae > subtribe Helianthinae > Helianthus
Sibling taxa
H. agrestis, H. angustifolius, H. annuus, H. anomalus, H. argophyllus, H. arizonensis, H. atrorubens, H. bolanderi, H. californicus, H. carnosus, H. ciliaris, H. cusickii, H. debilis, H. decapetalus, H. deserticola, H. divaricatus, H. eggertii, H. exilis, H. floridanus, H. giganteus, H. glaucophyllus, H. gracilentus, H. grosseserratus, H. heterophyllus, H. hirsutus, H. laciniatus, H. laevigatus, H. longifolius, H. maximiliani, H. microcephalus, H. mollis, H. neglectus, H. niveus, H. nuttallii, H. occidentalis, H. paradoxus, H. pauciflorus, H. petiolaris, H. porteri, H. praecox, H. pumilus, H. radula, H. resinosus, H. salicifolius, H. schweinitzii, H. silphioides, H. simulans, H. smithii, H. strumosus, H. verticillatus, H. ×laetiflorus
H. agrestis, H. angustifolius, H. annuus, H. anomalus, H. argophyllus, H. arizonensis, H. atrorubens, H. bolanderi, H. californicus, H. carnosus, H. ciliaris, H. cusickii, H. debilis, H. decapetalus, H. deserticola, H. divaricatus, H. eggertii, H. exilis, H. floridanus, H. giganteus, H. glaucophyllus, H. grosseserratus, H. heterophyllus, H. hirsutus, H. laciniatus, H. laevigatus, H. longifolius, H. maximiliani, H. microcephalus, H. mollis, H. neglectus, H. niveus, H. nuttallii, H. occidentalis, H. paradoxus, H. pauciflorus, H. petiolaris, H. porteri, H. praecox, H. pumilus, H. radula, H. resinosus, H. salicifolius, H. schweinitzii, H. silphioides, H. simulans, H. smithii, H. strumosus, H. tuberosus, H. verticillatus, H. ×laetiflorus
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. Treatment author: Edward E. Schilling. FNA vol. 21, p. 168. Treatment author: Edward E. Schilling.
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