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girasole, Jerusalem artichoke, Jerusalem sunflower, topinambour, tuberous sunflower

neglected sunflower

Habit Perennials, 50–200+ cm (rhizomatous, producing tubers late in growing season). Annuals, 80–200 cm.
Stems

erect, scabro-hispid to hirsute (sometimes glaucous).

erect (leafy), ± hispid to glabrate.

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; alternate;

petioles 7–12 cm;

blades deltate-ovate, 7–14 × 7.5–12.3 cm, bases usually ± cordate, sometimes truncate, margins subentire to serrulate, abaxial faces strigose, not gland-dotted.

Peduncles

1–15 cm.

10–40 cm.

Involucres

hemispheric, (10–25 ×) 8–12 mm.

± hemispheric, (23–28 ×) 10–14 mm.

Ray florets

10–20;

laminae 25–40 mm.

21–31;

laminae 29–39 mm.

Disc florets

60+;

corollas 6–7 mm, lobes yellow;

anthers dark brown or black, appendages dark or yellowish.

150+;

corollas 6–6.5 mm, lobes reddish;

anthers dark, appendages purplish (style branches reddish).

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.

25–35, lanceolate, 14–25 × 2.3–4 mm (surpassing discs), apices long-attenuate, abaxial faces strigillose to hispid.

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.

4–5 mm, strigillose to glabrate;

pappi of 2 aristate scales 2.8–3.2 mm.

Paleae

8–9 mm, 3-toothed (apices hairy).

9–10 mm, 3-toothed (middle teeth ± ciliate or bearded, hairs whitish, 0.3–0.6 mm).

2n

= 102.

= 34.

Helianthus tuberosus

Helianthus neglectus

Phenology Flowering late summer–fall. Flowering summer–fall.
Habitat Roadsides, fields, waste areas Sandy soils, sand dunes
Elevation 0–1000(–1500) m (0–3300(–4900) ft) 800–1100 m (2600–3600 ft)
Distribution
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]
from FNA
NM; TX
[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.)

Of conservation concern.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 21, p. 161. FNA vol. 21, p. 153.
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. gracilentus, H. grosseserratus, H. heterophyllus, H. hirsutus, H. laciniatus, H. laevigatus, H. longifolius, H. maximiliani, H. microcephalus, H. mollis, 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) Heiser: Rhodora 60: 275, fig. 2. (1958)
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