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Montana Field Guide

Montana Field Guides

Tansy Ragwort - Senecio jacobaea

Noxious Weed: Priority 2A
Exotic Species (not native to Montana)

Global Rank: GNR
State Rank: SNA

Agency Status
USFWS:
USFS:
BLM:
MNPS Threat Rank:
C-value: 0

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General Description
Short-lived, taprooted perennial. Stems erect, 20–80 cm. Herbage sparsely arachnoid. Leaves mainly cauline at flowering; blades narrowly oblanceolate, deeply divided into dentate lobes, 4–20 cm long, becoming sessile above. Inflorescence corymbiform with 10 to 60 heads. Heads radiate; involucres 4–6 mm high; phyllaries ca. 13, glabrous. Rays ca. 13; ligules 6–10 mm long. Disk corollas 4–5 mm long. Achenes 1–2 mm long, puberulent (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Range Comments
Introduced to northeast and northwest N. America; native to Europe (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Summary of Observations Submitted for Montana
Number of Observations: 8

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Relative Density

Recency

 

(Observations spanning multiple months or years are excluded from time charts)



Habitat
Disturbed soil of open forest, meadows, often associated with timber harvest or fire; valleys (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

References
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Citation for data on this website:
Tansy Ragwort — Senecio jacobaea.  Montana Field Guide.  .  Retrieved on , from