Illinois Natural History Survey - University of Illinois

Ambrosia psilostachya
Western ragweed, Perennial ragweed
Taxonomy

Synonyms: Ambrosia psilostachya var. coronopifolia

Subspecific taxa:

Classification:

Other taxonomic & nomenclature sources: USDA PlantsITISThe Plant ListIPNI

Images

   
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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

Collection & Observation Phenology [?]

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J
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Collection & Observation Timeline [?]

Species Status

Status/Listing: No Information

Notes:

Origin: North America

Species Description

General: Dicot-herb, perennial

Roots: adventitious, fibrous, rhizomes

Shoots: alternate, opposite leaf arrangment; simple leaf type; lobed (pinnately), parted (pinnately) leaf margin; Pinnate leaf venation; oblong leaf shape

Inflorescence: raceme, spike, head

Flowers: unisexual, monoecious; incomplete, not sepals; yellow, green; epigynous ovary position

Fruit: achene

Physiology: autotrophic

Ecology & Natural History

Habitat: Along railroads, in weedy habitats; disturbed sandy soils; old cemeteries, waste ground.

ILPIN Notes: Similar in appearance to Ambrosia artemisiifolia, but with a creeping rhizome, and thicker, short-petrolate to such sessile leaves. Wodo house says all these Ambrosia species probably are allergenic. Probably an early and unagressive introduction from west of Illinois, though may be native.

Functional Relationships:

  • Pollinators insects (wind)

Human Relationships:

  • Edibility [?] :
  • Showy Flowers:

Wildlife and Livestock Information:

  • Food Value:
  • Cover Value:

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

  • Entire State: 2
  • Chicago Area:

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