Ontario Weeds: Eastern black nightshade

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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. Herbicide resistance
  13. Photos
  14. References
  15. Related links

Scientific name:

  • Solanum ptycanthum Dun.

Other names:

  • morelle noire de l'est, Black nightshade, Deadly nightshade, SOLPT

Family:

  • Nightshade or Potato Family (Solanaceae)

General description:

  • Eastern black nightshade is an annual reproducing only by seed.

Habitat:

  • Eastern black nightshade occurs throughout southern Ontario in open dry woods, edges of pastures, waste places, and in cultivated land, especially in row crops.

Seedlings:

  • Hypocotyl (stem below cotyledon) are hairy and can be green or maroon
  • Cotyledon is oval, smooth and green on the upper surface, maroon on lower surface

Stems:

  • Stems erect, 5-100 cm (2-40 in.) high
  • Very branched in the upper part of the stem
  • Mostly hairless

Leaves

  • Alternate (1 per node)
  • Oval or diamond shaped
  • Pale green, soft and nearly translucent

Flowers & fruit:

  • Flowers are small and usually grouped together in a small umbel of 2 to 5 flowers
  • Flowers extend from a short stalk from the side of the stem
  • Petals are white and may or may not be tinged with purple
  • Resemble potato flowers but are smaller at 9-15 mm in diameter
  • fruits are black berries that are first green and contain many flat seeds
  • Berries are reputed to be poisonous
  • Flowers from June until late autumn

Roots and underground structures:

Eastern black nightshade has a slender taproot with branched fibrous root system.

Often confused with / Distinguishing features

It is often mistaken for pigweed seedlings. Eastern black nightshade is distinguished from other weeds as it is an annual plant that has thin, oval to diamond shaped leaves, small umbels of white flowers on the side of stems and black berries when mature.

Herbicide resistance

Sulphonylurea and imidazolinone resistant (WSSA group 2) populations exist in Ontario.

Photos

Figure 1: Eastern black nightshade seedling at the 2-leaf stage

Figure 1: Eastern black nightshade seedling at the 2-leaf stage

Figure 2: Eastern black nightshade leaf

Figure 2: Eastern black nightshade leaf

Figure 3: Eastern black nightshade flower

Figure 3: Eastern black nightshade flower

Figure 4: Immature green fruit of Eastern black nightshade that will turn black at maturity

Figure 4: Immature green fruit of Eastern black nightshade that will turn black at maturity

Figure 5: Mature Eastern black nightshade

Figure 5: Mature Eastern black nightshade

References

http://www.weedinfo.ca/en/weed-index/view/id/SOLPT

http://www.omafra.gov.on.ca/english/crops/facts/ontweeds/eblack_nightshade.htm

Related links

... on general Weed topics
... on weed identification, order OMAF and MRA Publication 505: Ontario Weeds
... on weed control, order OMAF and MRA Publication 75: Guide To Weed Control

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