Species: Helianthus tuberosus L.

comments | credits | copyright

Back to: Plants at Risk in Saskatchewan

Helianthus tuberosus L.

Species Image Gallery
(opens in a new window)

TAXONOMY

Family:

Asteraceae or Compositae

Genus:

Helianthus

Species Synonyms:

Helianthus tomentosus Michx.
Helianthus tuberosus var. subcanescens Gray

Common Names:

Jerusalem artichoke
Jerusalem sunflower

DISTRIBUTION

Canada:

southeastern Saskatchewan – Ontario

Saskatchewan:

southeastern Saskatchewan; Souris River Valley and Antler River Valley

Ecoregion:

Moist Mixed Grassland, Aspen Parkland

HABITAT

Saskatchewan:

semi-shaded or wooded river shores

Associated Species:

Acer negundo, Bromus inermis, Bromus latiglumis, Elymus virginicus, Galium triflorum, Prunus virginiana, Sonchus arvensis, Stachys palustris, Thalictrum dasycarpum

RARITY STATUS

Provincial Status According
to Harms (2003):

Threatened

Nature Conservancy Status:

G5 S2

Saskatchewan Species at
Risk Status:

None

COSEWIC Status:

None

Helianthus tuberosus is highly regionally restricted in the province, occurring only in the southeast corner. These populations represent the northern and western expansion of this species.

SPECIES DESCRIPTION

Height:

1 – 3 m tall

Roots:

fibrous; cigar-shaped, semi-edible tubers on rhizomes

Stems:

thick, firm, branched above, hirsute to scabrous, occasionally glabrous

Leaves:

cauline, opposite, uppermost alternate, abruptly tapered at base to petiole, 10 – 25 cm long, 6 – 15 cm wide, ovate to broadly lanceolate, 3-nerved for at least half of blade length, veins yellow on underside of leaf, adaxial surface scabrous, abaxial surface puberulent, margin serrate

Inflorescence:

heads several, 1 – 2.5 cm broad; peduncles scabrous; phyllaries in 3 series, equal to or slightly exceeding disc, loose or reflexed at maturity, lanceolate, apex acute to acuminate; receptacle low convex, chaff pubescent at apex

Flowers:

ligulate florets 5 – 15, 2 – 4 cm long, to 1 cm wide, 3 apical teeth, pistillate, infertile, yellow; tubular florets numerous, perfect, fertile, yellow

Fruits:

achenes 5 – 7 mm long, glabrous; pappus two deciduous awns

*KEY TO HELIANTHUS* SPECIES IN SASKATCHEWAN**

1 Annuals; taproots; leaves mostly alternate; receptacle flat or nearly so	2
1 Perennials; tough creeping rhizomes or erect branching crowns; leaves mostly opposite (upper leaves commonly alternate); receptacle convex or low conical	3

2 Lower leaves cordate and toothed, pubescence rough; involucral bracts attenuate with conspicuously hairy margins; central chaff not very hairy	H. annuus
2 Lower leaves not cordate, entire; involucral bracts gradually attenuate and not conspicuously hairy; central chaff with white hairs at apex	H. petiolaris ssp. petiolaris

3 Disc flowers dark brown, purple, or red	4
3 Disk flowers yellow or brown	5

4 Plants 1 – 2 m tall; leaves in 7 or more pairs; blade ovate to oblanceolate, 8 – 20 cm long, apex long-acuminate	H. pauciflorus ssp. pauciflorus
4 Plants < 1.2 m tall; leaves in 5 – 7 pairs; blade rhombic to lanceolate, 5 – 12 cm long, apex acute to obtuse	H. pauciflorus ssp. subrhomboideus

5 Involucral bracts appressed to the disk, imbricate	H. pauciflorus ssp. pauciflorus
5 Involucral bracts loose-spreading, all about the same length	6

6 Rootstocks with tubers; leaves ovate to broadly lanceolate, generally 3 times as long as wide	H. tuberosus
6 Rootstocks without tubers; leaves lanceolate to linear lanceolate, generally at least 3 times as long as wide	7

7 Middle leaves may be folded lengthwise, scabrous above, occasionally below	H. maximiliani
7 Middle leaves always flat, rough hispid to tomentose above, rough hispid to villous-tomentose below	8

8 Stems 20 – 30 dm tall; upper leaves alternate, lanceolate and acute to acuminate	H. nuttallii ssp. nuttalli
8 Stems 5 – 20 dm tall; upper leaves mostly opposite, lanceolate-ovate, acute to obtuse	H. nuttallii ssp. rydbergii