Amorphophallus titanum, the titan arum, is a flowering plant in the family Araceae. It has a large unbranched inflorescence; a tall single leaf, branched like a tree; and a heavy tuber which enables the plant to produce the inflorescence. A. titanum is endemic to rainforests on the Indonesian island of Sumatra.
Because its flower blooms infrequently and only for a short period, it gives off a powerful scent of rotting flesh to attract pollinators. As a consequence, it is characterized as a carrion flower, earning it the names corpse flower or corpse plant.
Etymology
A. titanum derives its name from Ancient Greek (ἄμορφοςamorphos, "without form, misshapen" + φαλλόςphallos, "phallus", and ΤιτάνTitan, "titan, giant").[2] The common name corpse flower is translated from the Indonesian name bunga bangkai with the same meaning.[3]
Life-cycle
Titan arum life-cycle
Leaf
A single leaf, the size and shape of a small tree, grows from the seed. The leaf grows on a patterned green and white petiole or stalk that branches into three sections at the top, each containing many leaflets. The leaf can reach up to 6 m (20 ft) tall and 5 m (16 ft) across. The petiole bearing the leaf can be 38 to 41 centimetres (15 to 16 in) thick at soil level and 30 to 32 centimetres (12 to 13 in) high at breast height.[4] Food from the leaf accumulates in an underground tuber. After a period of a year to 18 months, the old leaf dies, and a new one grows in its place from the tuber.
Tuber
When the tuber has stored enough energy, it becomes dormant for about four months. Then the process of producing a leaf which supplies food to the tuber repeats. The tuber is the largest known, typically weighing around 50 kg (110 lb).[5]
Inflorescence
After some years, when the tuber is sufficiently large, the titan arum develops an inflorescence instead of a leaf. This can reach over 3 m (10 ft) in height.[6][7] Like the related cuckoo pint and calla lily, it consists of a fragrant spadix of flowers wrapped by a spathe, which looks like a large petal. In the case of the titan arum, the spathe is a deep green on the outside and dark burgundy red on the inside, with a deeply furrowed texture. The spadix is almost hollow and resembles a large baguette. Near the bottom of the spadix, hidden from view inside the sheath of the spathe, the spadix bears two rings of small flowers. The upper ring bears the male flowers and the lower ring is spangled with the bright red-orange carpels of female flowers. The female flowers open first, and the male flowers open a day or two later. That usually prevents the flower from self-pollinating.
Pollination by carrion insects
As the spathe gradually opens, the spadix heats up to 37 °C (99 °F), and rhythmically releases a powerful odor to attract carrion insects which feed on or lay their eggs in rotting meat.[7] The potency of the odor gradually increases from late evening until the middle of the night, when carrion beetles and flesh flies are active as pollinators, then tapers off towards morning.[8] Analyses of chemicals released by the spadix show the stench includes dimethyl trisulfide (like limburger cheese), dimethyl disulfide (garlic), trimethylamine (rotting fish), isovaleric acid (sweaty socks), benzyl alcohol (sweet floral scent), phenol (like Chloraseptic), and indole (like feces).[9][10] The odor is detectable up to a half mile (0.8 km) away.[11] The inflorescence'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 roughly human body temperature, which helps the perfume volatilize. The heat helps to convince carrion-feeding insects that a dead body is present, attracting them to the inflorescence.[7]
Fruits and seeds
The carpels of pollinated female flowers ripen into fruits. The spathe and the upper part of the spadix wither away, leaving a short spike bearing a column of bright red fruits. These attract rhinoceros hornbills which eat the fruits and disperse the seeds around the rainforest. The spike dies back after around nine months, and the tuber becomes dormant for about a year. It can then produce a new leaf and restart the cycle.[8]
The plant produces a single leaf at a time.
A tuber weighing 117 kg, which produced three inflorescences simultaneously in May 2006 at the Botanic Gardens, Bonn
The tallest inflorescence was recorded at Meise Botanic Garden, Belgium, on 13 August 2024. It measured 322.5 cm from the tuber.
Male (above, yellow) and female (below, brownish-purple) flowers at the base of the spadix
Titan arum spike with fruits
Distribution
Amorphophallus titanum is endemic to western Sumatra,[6] where it grows in openings in rainforests on limestone hills.[12]
Taxonomy
Amorphophallus titanum was first scientifically described in 1878 by the Italian botanistOdoardo Beccari.[13]
The titan arum first flowered in cultivation at the Royal Botanic Gardens, Kew, London, in 1889,[14] grown from the single seedling that Kew received from Beccari.[8] The first documented flowerings in the United States were at the New York Botanical Garden in 1937 and 1939.[15] That flowering inspired the designation of the titan arum as the official flower of the Bronx in 1939, replaced in 2000 by the day lily.[16] In the Botanical Gardens of Bonn, the titan arum has been cultivated since 1932.[17] The number of cultivated plants has increased because the cultivation requirements for garden specimens are known in detail, and it has become common in the 21st century for five or more flowerings to occur in gardens around the world in a single year.[18] Challenging cultivation constraints mean that the plant is rarely cultivated by amateur gardeners, but in 2011, Roseville High School in California became the first school in the world to bring a titan arum to bloom.[19]
The largest tuber so far recorded was grown at the Royal Botanic Garden Edinburgh in 2010, which weighed 153.9 kg (339 lb) after seven years' growth from an initial tuber the size of an orange.[20]
The tallest documented inflorescence was at Meise Botanic Garden; on 13 August 2024 it reached 3.225 metres (10.58 ft) in height.[21]
In cultivation, the titan arum generally requires five to ten years of vegetative growth before blooming for the first time. After a plant's initial blooming, there can be considerable variation in its blooming frequency. The cultivation conditions are known in detail.[18] Some plants may not bloom again for another seven to ten years, while others may bloom every two or three years. At the botanical gardens in Bonn, under optimal cultivation conditions, the plants flowered every other year.[6][17] A plant has flowered every second year (2012 to 2022) in the Copenhagen Botanical Garden.[22] Anomalous flowerings have been documented, including consecutive blooms within a year,[23] and a tuber simultaneously sending up both a leaf (or two) and an inflorescence.[24] Triplet inflorescences have been recorded from Bonn, Germany (from a 117 kilograms (258 lb) tuber),[7][25] and at the Chicago Botanic Garden in May 2020.[26] Titan arums have bloomed at three of Indonesia's botanical gardens: Kebun Raya Bogor,[27]Kebun Raya Cibodas,[28] and Kebun Raya Purwodadi.[29]
Self-pollination was once considered impossible but, in 1992, botanists in Bonn successfully hand-pollinated their plant with its own pollen, using ground-up male flowers, resulting in fruiting and hundreds of seeds, from which numerous seedlings were produced and distributed.[6][17][18] A titan arum at Gustavus Adolphus College in Minnesota produced viable seed through self-pollination in 2011.[30]
^ abcdBarthlott, W., Szarzynski, J., Vlek, P., Lobin, W., & N. Korotkova (2009): A torch in the rainforest: thermogenesis of the Titan arum (Amorphophallus titanum). Plant Biol. 11 (4): 499–505 doi:10.1111/j.1438-8677.2008.00147.x
Barthlott, W., Szarzynski, J., Vlek, P., Lobin, W., & N. Korotkova (2009): A torch in the rainforest: thermogenesis of the Titan arum (Amorphophallus titanum). Plant Biol. 11 (4): 499–505 doi:10.1111/j.1438-8677.2008.00147.x
Bown, Deni (2000). Aroids: Plants of the Arum Family. Timber Press. ISBN0-88192-485-7
Korotkova, N. & W. Barthlott (2009): On the thermogenesis of the Titan arum (Amorphophallus titanum). Plant Signaling & Behavior 4 (11): 1096–1098 doi:10.4161/psb.4.11.9872
Lobin, W., Neumann, M., Radscheit, M. & W. Barthlott (2007): The cultivation of Titan Arum (Amorphophallus titanum) – A flagship species for Botanic Gardens, Sibbaldia 5: 69–86
Association of Education and Research Greenhouse Newsletter, volume 15 number 1.
_-_2.jpg)
.jpg)
_Titan_Arum,_tuber_117_kg,_May_2006,_Foto_%C2%A9_W._Barthlott,_Bot.Gard._Bonn.jpg)
_Titan_Arum_Foto_%C2%A9_W._Barthlott,_Bot.Gard._Bonn.jpg)
