What is the largest flower in the world, found in the rainforests of Sumatra?

Rafflesia arnoldii produces the largest individual flower in the world, and it is native to the rainforests of Sumatra and Borneo. Its enormous reddish-brown bloom can approach a meter in diameter and smells of rotting flesh, which attracts carrion-loving flies that help pollinate it.

The plant is extraordinarily unusual because it has no visible leaves, stems, or roots and contains no chlorophyll. Instead, it is a holoparasite that lives inside vines of the genus Tetrastigma. For most of its life, Rafflesia is hidden within its host; the giant flower is essentially the only part visitors see.

A common mix-up is the titan arum, or Amorphophallus titanum, which is also native to Sumatra and is often called a corpse flower. Titan arum produces the world’s largest unbranched inflorescence—a structure made of many tiny flowers—whereas Rafflesia produces the largest single flower. Rafflesia arnoldii was named after naturalist Joseph Arnold, who encountered it in Sumatra in 1818.