Flowers of the genus Rafflesia are the largest and perhaps rarest in the world. They take from 9 to 21 months to bud, and then bloom for just a week:

The Rafflesia has no leaves, stem or roots. It grows invisibly inside the roots of certain woody vines of the genus Tetrastigma. The Tetrastigma are rather common in the tropical jungles of Southeast Asia and related to the grapevine, but the Rafflesias seem to prefer only about three specific species. Not unlike fungi, the Rafflesias spend most of their life as tiny threads that penetrate their host vine. But it produces a flower with stamens and pistils, and develops into a fruit with seeds. It is difficult to find Rafflesias in the jungle and normally they can only bee seen when they are ready to reproduce, which is when they bloom. In its early visible stages the Rafflesia is a protuberance that grows from the bark of its host and develops into a bud the size and appearance of a reddish-brown cabbage. Normally the buds are found on the jungle floor but occasionally a flower may develop somewhat above the ground. Because the buds and flowers are found on the Tetrastigma vines, the locals in Sabah claim that the vine is a plant that produces the Rafflesia…

Most buds rot before they attain maturity, but when they finally open after nine or more months they display five huge, fleshy petals that can reach in extreme cases almost one meter in diameter and weigh over seven kilogrammes. Whoever has been lucky and seen the humungous flower knows that it is simply breathtaking. Of a vivid to velvety deep red it is normally spotted white, giving it the appearance of a slab of meat. Together with this appearance come one or more gallons of nectar of a sweet-foul smell reminiscent of rotting flesh to attract flies which pollinate the flower. In the centre there is a spiked disk to which stigma or stamens are attached, depending on the sex of the plant. After 3-4 days the flower disintegrates into a slimy mess, leaving behind a fruit of some 15 cm in diameter and containing thousands of tiny, hard-coated seeds to squirrels and other small animals that are thought to be responsible for the distribution of the Rafflesia. However, it is yet unclear as to how the propagating process fully works as pollination in Rafflesia seems to be a rare occurrence. Rafflesias are unisex and in order to have successful reproduction the insect pollinators have to visit a mature male and a mature female plant. But Rafflesias are for the most part found only in proximity of same-sex plants, and a mature plant of the other sex might not be blooming in close proximity. To complicate matters is the fact that the flowers last less than a week, leaving but a narrow window of opportunity for pollination.

There doesn’t seem to be any practical purpose for the flower to be so large. Perhaps having stolen their resources, the parasite can afford to waste it in extravagance. But for sure the spotting of a Rafflesia in its natural habitat is a moving experience!

Earlier this month a new species of Rafflesia was discovered in the Philippines.

FOLLOWUP: Videos of Rafflesia in bloom.