Illinois Natural History Survey - University of Illinois

Helianthus giganteus
Giant sunflower, Tall sunflower
Taxonomy

Synonyms:

Subspecific taxa:

Classification:

Other taxonomic & nomenclature sources: USDA PlantsITISThe Plant ListIPNI

Species Distribution
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County Map Legend
Absent:
Not known from county
Medium confidence:
Medium or unknown confidence;
often old records or unverifiable observations
Medium-high confidence:
Often observations by expert botanists
High confidence:
Often vouchered herbarium records
Planted / introduced:
Native species introduced outside historic range,
or only in planted locations within county (e.g., restorations)
Historic / extirpated:
Only historic records for the species; likely extirpated
(Note that this category is not yet functional)

North American distribution maps for this species: FLNAUSDA PlantsBONAPBISON

Collections, Observations & Flowering by Month [?]

J
0
F
0
M
0
A
0
M
0
J
0
J
0
A
0
S
0
O
0
N
0
D
0

Collections & Observations by Decade [?]

Species Status

Status/Listing: State Endangered

Notes:

Origin: Native

Species Description

General: Dicot-herb, perennial

Roots: adventitious, rhizomes

Shoots: alternate, opposite leaf arrangment; simple leaf type; serrate leaf margin; Pinnate leaf venation; oblong leaf shape

Inflorescence: head

Flowers: perfect; 5 merous; complete, regular, irregular; yellow; epigynous ovary position

Fruit: achene

Physiology: autotrophic; C3 C02 fixation

Reproduction: sexual, vegetative

Ecology & Natural History

Habitat: sand deposits. In N. Illinois, possibly in decadent tamarack bogs, calcareous fens.

ILPIN Notes: Possible use as breadstuffs, oil source, soup, & coffee substitute. disk flowers perfect & fertile; ray florets sterile. heads radiate; lower leaves opposite; disk & rays are yellow. Versus its closest relatives, H. grosseserratus & H. nuttallii, this species has: 1-nearly sessile leaves; 2-hairy stems; 3-preponderance in wet habitats. Rogers et al.

Functional Relationships:

  • Pollinators:
  • Dispersal:
  • Mycorrhizae:
  • N2 fixation:

Human Relationships:

  • Edibility [?] :
  • Showy Flowers:

Wildlife and Livestock Information:

  • Food Value:
  • Cover Value:

Coefficient of Conservatism (C-value) [?] :

  • Entire State: 9
  • Chicago Area: 9

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