Ontario Weeds: Common groundsel

Table of Contents

1. Name
2. Other Names
3. Family
4. General Description
   • Photos and Pictures
5. Stems and Roots
6. Flowers and Fruit
7. Habitat
8. Similar Species
9. Related Links

Name: Common groundsel, Senecio vulgaris L.,

Other Names: séneçon vulgaire, séneçon commun

Family: Composite or Aster Family (Compositae) 

General Description: Annual, reproducing only by seed.

Photos and Pictures

Stems & Roots: Stems erect or somewhat reclining, often branched, 10-60cm (4-24in.) high, smooth, somewhat fleshy; leaves alternate (1 per node), slightly fleshy, variable in shape from smooth and almost without teeth to shallowly or deeply lobed, with the lobes finely to coarsely and irregularly toothed; lower leaves stalked, upper ones stalkless and often clasping the stem.

Flowers & Fruit: Flower heads stalked in clusters at the end of stems and branches; each flower head 5-10mm (1/5-2/5in.) across, cylindrical or conic, without ray florets; disk florets yellowish; involucral bracts (surrounding each flower head) small, overlapping, usually with distinct black tips; seeds small, short-hairy, with a prominent, white, hairy pappus. Flowers from June to late autumn.

Habitat: Common groundsel occurs throughout Ontario, often very abundantly, in gardens, row crops, waste places and roadsides.

Similar Species: Young plants can be distinguished by their irregularly lobed and toothed leaves without white milky juice; older plants by their small conic-cylindrical flower heads with black-tipped involucral bracts around the base of each head.

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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