Facts about the Titan Arum

Latin name: Amorphophallus titanum

Other names: Titan Arum, Corpse flower, Bunga Bangkai

Native habitat: equatorial rainforests of central Sumatra in Indonesia

Family: Titan Arum is a member of the Family Araceae, the Aroids or Arum plants. Members of this family include the Calla Lily, Jack-in-the-Pulpit, Anthuriums, Dieffenbachia and Philodendrons. A related species in the family is the Giant Arum, Dracontium gigas, which is also blooming in the UW-Madison Botany greenhouses.

First discovered: Italian botanist Odoardo Beccari discovered the Titan Arum in Sumatra in 1878. He sent seeds to England's Royal Botanic Gardens in Kew, where the first bloom of this species in cultivation occurred in 1889.

Known bloomings in the U.S.: less than 17 (list of other U.S. bloomings). The Titan Arum bloomed for the first time in the United States at the New York Botanical Gardens in 1937, where it became a sensation. A more recent bloom occurred at the Huntington Botanical Gardens on August 1, 1999. Billed the "world's largest flower," it was the first-ever flowering of one of these rare plants in California, and only the 11th recorded bloom in the United States. During the 19 days it was on public view, this Amorphophallus titanum drew 76,000 fans.

Diagram identifying the leaf, spadix, spathe, fruit and a young bud of Titan Arum Biology of the Titan Arum: The Titan Arum grows from a large tuber that can weigh over 170 pounds; the flowering stalk can reach 10 feet and open to a diameter of three to four feet. Thousands of flowers are hidden inside at the base of the spadix, the fleshy central column. The large, frilly-edged, leafy "skirt" enclosing the spadix is the spathe, which when open resembles an upturned, fluted bell with a maroon interior. Only when the spathe is completely unfurled are the flowers mature. This entire, giant flowering structure is called an inflorescence.

Male and female flowers are separate, with the female flowers receptive first, the male flowers releasing pollen the next day. In nature, this timing ensures cross-pollination with another Titan Arum flower; however, solitary cultivated blooms occasionally manage to self-pollinate.

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 flowers are successfully pollinated, the surrounding spathe eventually falls off, exposing the maturing seeds. When ripe, the cherry-sized fruits turn a bright orange-red, a color attractive to birds which pick the berries off, digest the flesh and excrete the "pit" or seed. In this way, the plant is dispersed in nature.

The fully open inflorescence emits a repulsive, "rotting-fish-with-burnt-sugar" scent. The odor, strongest at night, is to attract pollinators, which in Titan's Sumatran home are mainly carrion beetles and flesh flies. Most fly- and beetle-pollinated "carrion" flowers are similarly colored and perfumed.

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.

Thermal Images of Titan Arum During Bloom: The Titan Arum heats up during its bloom. Here are a few thermal photographs of the Titan Arum during its recent bloom – the colors in these images correspond to temperature (click photograph for larger images). White is the hottest, around human body temperature. In decreasing order, the next colors are red, yellow, green, blue and black, with black being the coolest.

Why do the Titans do this? The wonderful smell that these corpse flowers are famous for is composed primarily of fairly heavy, sulfur-based compounds that do not become airborne easily. The plant heats itself up in order to volatilize its "perfume," enabling the smell to go further, attract more flies, and increase the chance of pollination. To heat up, the plant "burns" stored carbohydrates, short-circuiting its basic respiratory process in order to maximize the production of heat. Many members of the Arum family perform metabolic burns like this, albeit on a smaller scale. Unfortunately, the enormous amount of energy the plant expends in attracting flies limits the amount of time it can bloom, which explains why these plants typically bloom for only a few days, and why they don't bloom every year.

On the Titan Arum at that time, the tip of the spadix (the central spike) was about human body temperature. The rest of the spadix was cooler (though still warmer than the surrounding air), but the surrounding spathe was cool and blue. Oddly enough, the spadix below the tip was not a uniform temperature. One edge was consistently warmer than the rest of the spike, as you can see in the images.

The images here were taken July 30, 2002, between 10:30 and 11:00 p.m. They were taken by Frank Landis with a thermal imaging (infra-red) camera on loan from the Wisconsin Energy Conservation Corporation. When these pictures were taken, the plant had just come into full bloom, and it was as hot (and stinky!) as it gets.

Visitors gather to view the 98-inch-tall Titan Arum nicknamed "Big Bucky," which bloomed June 9, 2005.
Photo by: Michael Forster Rothbart

Illustration of Titan Arum in bud, bloom and fruit
stages

Illustration: Kandis Elliot

This illustration shows Titan Arum in bud, left, and full bloom, center. At the base of the spadix (the fleshy central column) are over a thousand tiny flowers. If pollinated, these flowers will produce a huge ball of bright red berries, right.

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