The Rafflesia arnoldii is the world’s largest flower. Photograph by Harry Wiriadinata and Suwito Alam from article in Voice of Nature, v. 84, August 1990, p. 14.
Two views of the titan arum blooming in July 2013 at the United States Botanic Garden.The Titan arum is the plant with the world’s largest inflorescence, or cluster or flowers. Photo from the United States Botanic Garden Website.
The Rafflesia arnoldii.
The flower with the world’s largest bloom is the Rafflesia arnoldii. This rare flower is found in the rainforests of Indonesia. It can grow to be 3 feet across and weigh up to 15 pounds! It is a parasitic plant, with no visible leaves, roots, or stem. It attaches itself to a host plant to obtain water and nutrients. When in bloom, the Rafflesia emits a repulsive odor, similar to that of rotting meat. This odor attracts insects that pollinate the plant.
Another enormous flower found in Indonesia is the Amorphophallus titanum, or Titan arum. It is also known as the “corpse flower” for its unpleasant odor. Like the Rafflesia, the Titan emits the smell of rotting flesh to attract pollinators. Technically, the Titan arum is not a single flower. It is a cluster of many tiny flowers, called an inflorescence. The Titan arum has the largest unbranched inflorescence of all flowering plants. The plant can reach heights of 7 to 12 feet and weigh as much as 170 pounds!