Deadly nightshade (Atropa belladonna). The leaves and berries of this plant are highly poisonous and can prove deadly if ingested. Traditionally, deadly nightshade was used cosmetically as eyedrops to dilate the pupil. It is still used in optometry today for eye examinations. Deadly nightshade is a good source of atropine, an antidote for nerve agents. This plant can also be used recreationally as a hallucinogenic drug. Photographed at Monti Ernici, Lazio, Italy.