Black nightshade and Nightshade

Black nightshade noun - Eurasian herb naturalized in America having white flowers and poisonous hairy foliage and bearing black berries that are sometimes poisonous but sometimes edible.

Nightshade and black nightshade are semantically related. In some cases you can use "Nightshade" instead a noun phrase "Black nightshade".

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

Black nightshade and nightshade are semantically related. Sometimes you can replace phrase "Black nightshade" with "Nightshade", this terms are similar.