Nerium oleander is a shrub or small tree in the dogbane family 'Apocynaceae', toxic in all its parts. It is the only species currently classified in the genus Nerium. It is most commonly known as nerium or oleander, from its superficial resemblance to the unrelated olive Olea.

It is so widely cultivated that no precise region of origin has been identified, though southwest Asia has been suggested. Oleander is one of the most poisonous commonly grown garden plants.

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