Rafflesia arnoldii is a member of the genus Rafflesia. It is noted for producing the largest individual flower on earth, and a strong odor of decaying flesh - the latter point earning it the nickname of "corpse flower". It occurs only in the rainforests of Sumatra and Borneo in the Indonesian Archipelago. Although there are some plants with larger flowering organs like the Titan Arum and Talipot palm, those are technically clusters of many flowers.
Several species of Rafflesia grow in the jungles of southeast Asia, including the Philippines. Many of them are threatened or endangered. The flower of Rafflesia arnoldii is the largest which attains a diameter of nearly one meter (3 ft) and can weigh up to 11 kilograms (24 lb.
It lives as a parasite on the Tetrastigma vine, which grows only in primary (undisturbed) rainforests. Rafflesia lacks any observable leaves, stems or even roots, yet is still considered a vascular plant. Similar to fungi, individuals grow as thread-like strands of tissue completely embedded within and in intimate contact with surrounding host cells from which nutrients and water are obtained. Perhaps the only part of Rafflesia that is identifiable as distinctly plant-like are the flowers; although, even these are unusual since they attain massive proportions, have a reddish-brown coloration and stink of rotting flesh, which is why it was nicknamed the "corpse flower". This scent attracts insects such as flies which then pollinate the rare plant. It is not to be confused with the Titan Arum, Amorphophallus titanum, which is also commonly referred to as the "corpse flower.
Rafflesia arnoldii is rare and fairly hard to locate. It is especially difficult to locate the flower in forests as the buds take many months to develop and the flower lasts for just a few days. The flowers are unisexual and thus proximity of male and female flowers is vital for successful pollination. These factors make successful pollination a rare event.
How many of these plants still survive is unknown, but as the remaining primary forests of Borneo and Sumatra disappear, it can only be assumed that their numbers are dwindling. Many are known to be nearing extinction. Some environmentalists are thinking of a way to recreate the species' environment, in an effort to stimulate a recovery in the population of this endangered species. This has proved unsuccessful so far, but the efforts have continued. Steps are also being taken to conserve the forests of Sumatra and Borneo.