The Titan Arum (Amorphophallus titanum) is native to the equatorial rain forests on the island of Sumatra. There it is known as "Bunga Bangkai," meaning "Corpse Flower." This is due to its stench, which has been discribed as resembling "rotting-fish-with-burnt-sugar." This odor, which is strongest at night, is designed to attract pollinators, which in Sumatra are mainly carrion beetles and flesh flies.
In its natural state, the inflorescence of the Titan Arum can sometimes reach a height of 10 feet. None of the Titan Arums which have bloomed in "captivity" has reached this height. More typical in size is Mr. Stinky, which is shown on the left. Mr Stinky grew an inflorescence which reached a maximum height of 7'1" when it bloomed in May 2003. This is the exact same height as Shaquille O'Neill, who is shown at right.
An Italian botanist "discovered" the Titan Arum in Sumatra in 1878. (The residents of Sumatra had long been aware of it, of course.) He sent seeds to England's Royal Botanic Gardens in Kew, where the first bloom of this species in cultivation occurred in 1889.
A Titan Arum bloomed for the first time in the United States at the New York Botanical Gardens in 1937, where it became a sensation. Since then there have been about two dozen blooms in the United States. The photograph at right shows a bloom which occurred at the Huntington Library in Southern California in 1998.
The Titan Arum grows from a large tuber that can weigh over 170 pounds. For most of its life, the plant regularly produces a single, umbrella-like leaf that is itself quite "titanic." In the wild, this leaf can reach 20 feet tall and 15 feet across. In cultivation the leaf usually grows 12 feet high, with the stalk as thick as a person's thigh before branching into a single, compound leaf. An individual leaf lives for about a year. The tuber then enters a short dormant period before producing another leaf or (if you're very, very, lucky) a Bunga Bangkai. The bloom of a Titan Arum is called an inflorescence. Like all Aroids, this inflorescence consists of a spadix surrounded by a spathe. Thousands of flowers are hidden inside at the base of the thick, fleshy spadix. The spathe when open resembles a fluted upturned bell with a maroon interior. Only after the spathe is completely unfurled are the flowers mature and only then does the inflorescence emit its famous odor.
The spathe unfurls about 3 weeks after the bud tip first appears. The huge inflorescence opens abruptly (within hours) and typically stays open for only a few days. Collapse of the spadix takes place after three to five days. If the flowers were successfully pollinated, the surrounding spathe eventually falls off, exposing the maturing seeds. When ripe, the cherry-sized fruits turn a bright orange-red, which attracts birds, which pick the berries off, eat them, and excrete the seed. In this way, the plant is dispersed in nature.
The Titan Arum heats itself up during its bloom. The tip of the spadix will heat to about human body temperature, which can be seen in the thermal image from the University of Wisconsin, Madison, on the left. The rest of the spadix is cooler, though still warmer than the surrounding air.
The reason the Titans do this is that molecules which cause the famous stench are fairly heavy, sulfur based compounds that don't become airborne easily. The plant heats itself up in order to volatilize its "perfume," enabling the smell to travel further, attract more flies and beetles, and increase the chance of pollination.
The plant must expend an enormous amount of energy to do this, which limits the amount of time it can bloom. This explains why Titan Arums typically only bloom for a few days, and why they do not bloom every year.