Ontario Weeds: Hairy Galinsoga

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Excerpt from Publication 505, Ontario Weeds, Order this publication

Table of Contents

  1. Scientific name
  2. Other names
  3. Family
  4. General description
  5. Habitat
  6. Seedlings
  7. Stems
  8. Leaves
  9. Flowers and fruit
  10. Roots and underground structures
  11. Often confused with/distinguishing features
  12. Related Links

Scientific name:

Galinsoga ciliata

Other Names:

galinsoga cilié, Galinsoga, Quickweed

Family:

Composite or Aster Family (Compositae)

General description:

Hairy galinsoga is an annual weed reproducing only by seed.

Habitat:

Hairy galinsoga is found throughout southern Ontario especially near towns and cities in gardens, roadside and waste areas.

Seedlings:

  • Cotyledons are club-shaped, opposite, triangular with slightly toothed margins
  • Cotyledons are covered with hairs
  • Hypocotyl is very short and green but becomes maroon as it matures

Stems & Roots:

  • Stems are erect
  • Very branched with opposite branches
  • 20-70 cm in height
  • Covered with coarse spreading hair

Leaves

  • Leaves are opposite (2 per node)
  • Lower leaves have long stalks, upper leaves have very short stalks
  • Leafs are oval in shape and pointed towards the tip
  • Leaf margins are coarsely toothed

Flowers & Fruit:

  • Flower heads are small (3-7 mm across) on hairy stalks from axils of leaves
  • Ray florets are white with about 5 per head and slightly longer than the yellowish-green to whitish disk florets
  • Pappus scales present on both ray and tubular florets
  • Flowers from June to late autumn.

Roots and underground structures:

  • Fibrous root system

Often confused with/distinguishing features

Hairy galinsoga is distinguished by its opposite, oval, coarsely toothed leaves on opposite-branched stems as well as its small flower heads that each have 5 white tiny rays and a yellow disk.

Photos

Figure 1: Mature, whole plant of Hairy galinsoga

Figure 1: Mature, whole plant of Hairy galinsoga

Figure 2: Hairy galinsoga seedling at the 2-leaf stage

Figure 2: Hairy galinsoga seedling at the 2-leaf stage

Figure 3: Hairy stem of Hairy galinsoga

Figure 3: Hairy stem of Hairy galinsoga

Figure 4: Small flowers of Hairy galinsoga extending from the leaf axils

Figure 4: Small flowers of Hairy galinsoga extending from the leaf axils

Figure 5: Close up of a single flower of Hairy galinsoga

Figure 5: Close up of a single flower of Hairy galinsoga

Figure 6: Hairy galinsoga seeds

Figure 6: Hairy galinsoga seeds

References

Related Links

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