World's Largest Flower Threatened

Its smell is usually described as either "rotting flesh mixed with excrement" or "burnt sugar and rotten fish" depending on who you talk to.

Locals refer to it as a "corpse" and it can grow to a height of four meters.

It's huge. It's bizarre. It's a flower - and it's very endangered.

In July 2002, one of the largest flowers in the world, the titan arum, bloomed in the botanical garden of the University of Wisconsin. The flower is rare, both in its native habitat of Sumatra, Indonesia, and in greenhouse collections around the world. Rarer still are the blooms, which only occur once every few years. Cultivated titan arums in the United States have only been reported to have bloomed 17 times in the last century.

But when it does bloom it is a sight to behold, as the flower opens to a diameter of more than a meter across and exposes a bright crimson interior. The highest point on the flower, known as the spadix, is pale and towers over the human crowds who come to see this unusual plant. No doubt, they hold their noses. For biologists, the flower is a fascinating study.

The massive flower has developed an interesting evolutionary trait whereby the spadix heats up (amazingly to the temperature of a human body) in order to release its awful scent. The reason for the terrible smell is that it attracts pollinators like carrion beetles and sweat bees - insects specialized for decaying or sweating bodies.

Flowering lasts only a few days, then the plant wilts and collapses. If pollination was successful, the collapsing plant exposes red seed-bearing fruits to be eaten and distributed through the forest by birds.

After dying back, the flower enters a dormant stage until eventually a new shoot pops out of the ground. Most of the time, this shoot is destined to become a tall stem holding the plant's single, although massive, leaf. But every once and a while, the shoot becomes a flower - actually a mass of flowers that appears as one.

Researchers hypothesize that the reason the plant flowers so rarely and for such a short duration is because of the incredible amount of energy required to reach the blooming stage and to release the powerful scent. At its peak, the spadix can grow 20 centimeters a day!

Unfortunately, this strange giant is not likely to survive for much longer in the wild. Logging in Indonesia has removed most of its habitat and massive illegal logging operations threaten even "protected" areas like national parks, which are home to some of the world's last remaining orangutan and Sumatran rhinoceros populations.

According to the World Bank, at least 1.5 million hectares are lost every year. The situation is chaotic as illegal logging gangs compete with legitimate logging operations to cut the timber first. Last year, a group of scientists wrote in the journal Science that if the situation continues unabated, there will likely be no lowland Sumatran forests left by 2005.

That would be a terrible blow, because the rainforests of Sumatra are some of the most diverse and productive in the world. Many endangered species of plants, reptiles, mammals and birds live in these jungles, including the rhinoceros hornbill - a bird vital to the survival of the titan arums because it is very proficient at spreading the flower's seeds. According to Birdlife International, Sumatra is one of the world's bird extinction hotspots, where 17 species are threatened with extinction and another 73 are "near threatened."

The titan arum may smell bad, but it is an important part of a threatened forest ecosystem. Although Indonesia's president has vowed to crack down on illegal logging, the country is in economic turmoil and the problem continues. Help from the international community is badly needed if we are to have any hope of conserving these rich forests, which are a legacy for all humankind.

By David Suzuki