Ontario Weeds: Eastern black nightshade

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. Caution
9. Related Links

Name: Eastern black nightshade, Solanum ptycanthum Dun.

Other Names: SOLPT, morelle noire de l'est, Black nightshade, Deadly nightshade, often mistaken as Solanum nigrum L., and in the previous edition included under the name American nightshade, morelle d'Amerique, Solanum americanum Mill.

Family: Nightshade or Potato Family (Solanaceae)

General Description: Annual, reproducing only by seed. It is distinguished by being annual plant with thin, ovate to diamond-shaped leaves, small umbels of flowers on short stalks from sides of stems (not from leaf axils), small, white flowers, and small, black berries that are not partly enclosed by their expanded calyxes.

Photos and Pictures

Eastern black nightshade. A. Upper part of plant.

B. Portion of annual root system.

Stems & Roots: Stems erect, 5-100 cm (2-40 in.) high, usually much-branched in the upper part, mostly hairless; leaves alternate (1 per node), ovate or rhombic (diamond-shaped), pale green, soft, thin and nearly translucent.

Flowers & Fruit: Flowers small, usually 2 to 5 grouped together in a small umbel (flower stalks all from 1 point) on a short stalk sticking out from the side of the stem rather than from the axil of a leaf (angle between leaf and stem) as in most other plants; calyx of 5 united sepals with 5 pointed lobes, small and not enlarging with the fruit; petals white or white tinged with purple, united into a star-shaped corolla with 5 sharp lobes resembling the flower of a potato but much smaller, about 9 - 15 mm (1/3-2/5 in.) in diameter; the short anthers about 1.3-2 mm (1/20-1/12 in.) long, united and forming a yellow column in the centre of the flower; fruits are berries, always larger than the calyx, green at first but turning black and juicy when mature, 5-9 mm (1/5-1/3 in.) in diameter, containing several, small, flat seeds and 4 to 8 small, hard, irregular stone-like crumbs. Flowers from June until late autumn.

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.

Caution: The berries of Eastern black nightshade are reputed to be poisonous and thus the plant is sometimes called "deadly nightshade," a name belonging to a different plant. Until more information is available about their palatability, it is advisable not to eat these attractive berries. Feeding experiments have demonstrated that this plant can be toxic to cattle if it comprises about 25% or more of the forage intake. 

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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