The titan arum or Amorphophallus titanum (from Ancient Greek amorphos, "without form, misshapen" + phallos, "penis", and titan, "giant") is a flowering plant with the largest unbranched inflorescence in the world. The largest single flower is borne by the Rafflesia arnoldii; the largest branched inflorescence in the plant kingdom belongs to the Talipot palm (Corypha umbraculifera). The titan arum was originally discovered by an Italian botanist, Odoardo Beccari, in Sumatra in 1878. Though found in many botanic gardens around the world it is still indigenous only to the tropical forests of Sumatra. Due to its fragrance, which is reminiscent of the smell of a decomposing mammal, the titan arum is also known as a carrion flower, the "corpse flower", or "Corpse plant" (in Indonesian, "bunga bangkai" – bunga means flower, while bangkai means corpse or cadaver; for the same reason, the same title is also attributed to Rafflesia which, like the titan arum, also grows in the rainforests of Sumatra).
The popular name titan arum was invented by the broadcaster and naturalist Sir David Attenborough, for his BBC TV series The Private Life of Plants, in which the flowering and pollination of the plant were filmed for the first time. Attenborough felt that constantly referring to the plant as Amorphophallus on a popular TV documentary would be inappropriate.
The titan arum's inflorescence can reach over 3 metres (almost 10 ft.) in height. Like the related cuckoo pint and calla lily, it consists of a fragrant spadix of flowers wrapped by a spathe, which looks like the flower's single petal. In the case of the Titan Arum, the spathe is green on the outside and dark burgundy red on the inside, and deeply furrowed. The spadix is hollow and resembles a large loaf of French bread. The upper, visible portion of the spadix is covered in pollen, while its lower extremity is spangled with bright red-orange carpels. The "fragrance" of the inflorescence resembles rotting meat, attracting carrion-eating beetles and Flesh Flies (family Sarcophagidae) that pollinate it. The flower's deep red color and texture contribute to the illusion that the spathe is a piece of meat. During bloom, the tip of the spadix is approximately human body temperature, which helps the perfume volatilize; this heat is also believed to assist in the illusion that attracts carcass-eating insects.
After the flower dies back, a single leaf, which reaches the size of a small tree, grows from the underground corm. The leaf grows on a semi-green stalk that branches into three sections at the top, each containing many leaflets. The leaf structure can reach up to 6 m (20 ft) tall and 5 m (16 ft) across. Each year, the old leaf dies and a new one grows in its place. When the corm has stored enough energy, it becomes dormant for about 4 months. Then, the process repeats.
The titan arum grows only in the wild in the equatorial rainforests of Sumatra, Indonesia. It was first described in 1878 by Italian botanist Odoardo Beccari. The plant flowers only infrequently in the wild and even more rarely when cultivated. It first flowered in cultivation at the Royal Botanic Gardens, at Kew in London, in 1889, with over 100 cultivated blossoms since then. The first documented flowerings in the United States were at New York Botanical Garden in 1937 and 1939. This flowering also inspired the designation of the titan arum as the official flower of the Bronx in 1939, only to be replaced in 2000 by the day lily. The number of cultivated plants has increased in recent years, and it is not uncommon for there to be five or more flowering events in gardens around the world in a single year. The titan arum is more commonly available to the advanced gardener due to pollination techniques.
Until 2005, the tallest bloom in cultivation, some 2.74 m (8 ft. 11 in.) high, was achieved at the Botanical Gardens of Bonn, Germany in 2003. The event was acknowledged by the Guinness Book of Records (see the certificate).