Ontario Weeds: Tansy ragwort
Table of Contents
- Name
- Other Names
- Family
- General Description
- Stems and Roots
- Flowers and Fruit
- Habitat
- Caution
- Similar Species
- Related Links
Name: Tansy ragwort, Senecio jacobaea
L.,
Other Names: séneçon jacobée,
Stinking Willie, herbe de Saint-Jacques, jacobée
Family: Composite or Aster Family (Compositae)
General Description: Biennial or short-lived
perennial closely related to Common
groundsel.
Photos and Pictures
Tansy ragwort. A. Lower portion of plant. |
B. Top of flowering stem. |
Stems & Roots: It is usually a
taller plant (20-100cm, 8-40in.) with leaves broader in outline and
cobwebby-hairy below, more finely divided, not as fleshy, and with
their surfaces curled or crisped and wavy like leaf lettuce.
Flowers & Fruit: Flower heads in
a short, broad, nearly flat-topped cluster at the end of the stem;
each head with several, small, yellow ray florets 4-8mm (1/6-1/3in.)
long, a dense centre of yellow disk florets, and with involucral bracts
darker green but not black at their tips. Its odour is considered
unpleasant by many people. Flowers from July to October.
Habitat: Tansy ragwort occurs in only
a few isolated localities in southern Ontario in pastures, waste places,
along roadsides, and occasionally in gardens and lawns.
Caution: It is poisonous to livestock and
is responsible for Pictou disease of cattle, a serious problem in
Nova Scotia where the weed is widespread.
Similar Species: It is distinguished by
its deeply dissected leaves with curled or wavy surfaces, its erect
stature with somewhat flat-topped inflorescences and its flower heads
with yellow rays and yellow centres.
Related Links
... on general Weed
topics
... on weed identification, order OMAFRA Publication 505: Ontario Weeds
... on weed control, order OMAFRA Publication 75: Guide To Weed Control
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