Several weedlike relatives of the potato have poisons in their leaves, berries, or roots. These plants are called Nightshade, and their poisons range from mild to deadly. The common, or black, Nightshade grows about 12 inches high and has pointed, oval leaves, drooping clusters of white flowers, and small black berries. When eaten raw the common Nightshade can be poisonous, but when the plant is boiled its leaves may be eaten as a kind of green or its berries used in pies and preserves.

It is found in Europe and North America. Another plant of the Nightshade group is the Blue-Blossomed Bittersweet, or Woody Nightshade. Its foliage and egg-shaped scarlet berries taste both bitter and sweet and contain the chemical Solanine, which can cause convulsions and dealth if taken in large doses. The plant is found in the British Isles, Europe,Asia, and North America. Although poisonous, the deadly Nightshade, or Belladonna, is particularly valuable to medicine.