Jacobaea vulgaris
tansy ragwort
Asteraceae (Aster family)
Introduction to Vascular Plants
tansy ragwort
Asteraceae (Aster family)
Introduction to Vascular Plants
Introduction
Tansy ragwort is an invasive introduced species from Europe that is now found in eastern and western North America, but is absent from the prairies and midwestern states (United States: CA, ID, IL, IN, MA, ME, MI, MT, NJ, NY, OR, PA, WA, WY; Canada: BC, MB, NB, NF, NS, ON, PE, QC) (USDA 2010). It is poisonous to livestock (BC Ministry of Agriculture 2009). Biological control methods have been applied to it, including the introduction of the cinnabar moth (tiger moth) (Tyria jacobaeae) to North America, a species which feeds exclusively on tansy ragwort. In our region, tansy ragwort can be confused with common tansy (Tanacetum vulgare), however, tansy ragwort has yellow ray petals, while common tansy lacks ray petals. Tansy ragwort was first recorded in British Columbia at Nanaimo in 1950 (BC Ministry of Agriculture 2009). Flora North America Online provides a detailed description for this species. Read more about this species in BC.
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Species Information
General:
Biennial or short-lived perennial herb from a poorly-developed to evident taproot; stems erect, solitary or several, branched above, sparsely to densely white woolly-hairy, 0.2-1 m tall.
Leaves:
Basal leaves oblanceolate, stalked, 4-20 cm long including the stalk, 2-6 cm wide, mostly 2-3 times pinnately cut, thinly woolly-hairy when young but usually glabrous by flowering time; stem leaves similar, progressively reduced upwards, becoming unstalked.
Flowers:
Heads with ray and disk flowers, several to numerous in clusters; involucres 2-5 mm tall; involucral bracts oblanceolate, with long-pointed, usually black tips, hairless to sparsely woolly-hairy, margins translucent; bracteoles few, black-tipped; ray flowers yellow, 4-10 mm long; disk flowers yellow.
Fruits:
Achenes oblong, nerved, those of the disk flowers minutely coarse-hairy, those of the ray flowers glabrous; pappus of white hairlike bristles.
Illustration
If more than one illustration is available for a species (e.g., separate illustrations were provided for two subspecies) then links to the separate images will be provided below. Note that individual subspecies or varietal illustrations are not always available.
Illustration Source: The Illustrated Flora of British Columbia
Ecology
Ecological Framework for Jacobaea vulgaris
The table below shows the species-specific information calculated from
original data (BEC database) provided by the BC Ministry of Forests and Range.
(Updated August, 2013)
The table below shows the species-specific information calculated from
original data (BEC database) provided by the BC Ministry of Forests and Range.
(Updated August, 2013)
| Site Information |
Value / Class |
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|
Avg |
Min |
Max |
|
| Elevation
(metres) |
1370 | 1370 | 1370 |
| Slope
Gradient (%) |
40 | 40 | 40 |
|
Aspect (degrees) |
220 | 220 | 220 |
| Soil
Moisture Regime (SMR) [0 - very xeric; 4 - mesic; 8 - hydric] |
3 | 3 | 3 |
| Modal
Nutrient Regime
Class |
|||
| #
of field plots species was recorded in: |
1 | ||
| Modal
BEC Zone Class |
SWB | ||
|
All BEC Zones (# of stations/zone) species was recorded in |
SWB(1) | ||
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Source:
Klinkenberg 2013
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Habitat and Range
Mesic to dry fields, clearcuts and pastures in the lowland zone; locally frequent on S Vancouver Island and adjacent lower mainland; introduced from Eurasia.Status Information
Synonyms
Synonyms and Alternate Names:
Senecio jacobaea L.
Taxonomic Notes
Tansy ragwort is considered an emerging invasive species in the Vancouver region by the Greater Vancouver Invasive Plant Council (2009). An emerging invasive species is defined by them as species "currently found in isolated, sparse populations but rapidly expanding their range within the region". It is listed as one of the top fourteen species of concern by the Coastal Invasive Plant Council. Visit their web site.
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References
BC Ministry of Agriculture and Lands. 2009. Tansy Ragwort. Available Online.
USDA. 2010. Plant profile for Senecio jacobaea. USDA Plants Database. United States Department of Agriculture. Available Online.