The largest flower in the world, the rafflesia arnoldi, weighs 7 kg (15 pounds) and grows only on the Sumatra island of Indonesia. Its petals grow to ½ metre (1,6 feet) long and 2,5 cm (1 inch) thick.
There are 16 species of rafflesia, found in Sumatra, Malaysia and Borneo. The species is named after the naturalist Sir Stamford Raffles, who founded the British colony of Singapore in 1819. Raffles discovered the parasitic plant with his friend Dr. Joseph Arnold during their travels in May 1818. The rafflesia arnoldi is named after the two.
Several species of Rafflesia grow in the jungles of Southeast Asia, all of them threatened or endangered. Rafflesia arnoldii is the largest; its blossom attains a diameter of nearly a meter and can weigh up to 11 kg. Not only is it the world's largest flower, it is one of the most bizarre and improbable organisms on the planet.
It produces no leaves, stems or roots but lives as a parasite on the Tetrastigma vine, which grows only in primary (undisturbed) rainforest. Only the flower or bud can be seen; the rest of the plant exists only as filaments within its unfortunate host. The blossom is pollinated by flies attracted by its scent, which resembles that of carrion.
The Rafflesia is rare and fairly hard to locate. It is especially difficult to see in bloom; the buds take many months to develop and the blossom lasts for just a few days. How many of these strange plants still survive is unknown, but the last of them can be expected to vanish as the remaining primary forests of Borneo and Sumatra are burned.
However fascinating and beautiful the rafflesia arnoldi may be, it is also called "corpse flower" and really reeks, the latter to attract flies for pollination.
Of about 200,000 kinds of flowers in the world, the smallest is the duckweed, which can only be seen with a microscope.
