Nightshade and Poisonous nightshade

Nightshade noun - Any of numerous shrubs or herbs or vines of the genus Solanum; most are poisonous though many bear edible fruit.

Poisonous nightshade and nightshade are semantically related. In some cases you can replace phrase "Poisonous nightshade" with "Nightshade", this terms are similar.

Poisonous nightshade noun - Poisonous perennial Old World vine having violet flowers and oval coral-red berries; widespread weed in North America.

Nightshade and poisonous nightshade are semantically related. You can use "Nightshade" instead a noun phrase "Poisonous nightshade".