Learn more about this rare flowering plant that features the world’s largest inflorescence and an odor that draws carrion flies and beetles.
What is the titan arum?
The titan arum is a tropical plant native to Sumatra in Indonesia. Rarely encountered in the wild, it is a member of the Araceae, or arum family, which includes some 140 genera and over 4,000 species of plants. Most of the species diversity in the Araceae occurs in the New World tropics, although members are also distributed in the Old World tropics and northern temperate regions. Jack-in-the-pulpit and skunk cabbage are among the temperate, New World members of this plant family.
What is the name for this plant and what does it mean?
Amorphophallus titanum is the scientific name for the plant commonly referred to as the titan arum or the corpse plant. The genus name, Amorphophallus derives from the Latin words “amorphos” (without form or misshapen) and “phallos” (phallic-shaped), while its specific epithet (the second part of the Latin binomial) “titanum” (giant) refers to its tremendous size.
Is the titan arum the largest flower in the world?
Absolutely not! Its flowers are tiny. Instead, it is considered the world’s largest unbranched inflorescence. An inflorescence is a group or cluster of flowers arranged on a stem that is either branched or unbranched. The main axis of the titan arum inflorescence is huge, and huge numbers of small flowers are borne on the surface. Rafflesia arnoldii, also native to the tropical rain forests of southeast Asia including Sumatra and Borneo in Indonesia, produces the world’s largest single flower at about a meter (just over a yard) in width.
Where are the flowers located in a titan arum inflorescence?
The outer portion of the titan arum’s inflorescence is a purple, vase-like sheath called the spathe. This surrounds the spadix, a red tube-shaped structure that holds hundreds of tiny flowers hidden beneath the protective covering of the spathe. The flowers are unisexual, and female flowers are at the base with male (pollen producing) flowers higher up.
Do titan arum flowers have petals?
Titan arum flowers lack petals, which in many plants serve as a visual indicator to pollinators seeking pollen and nectar. Instead of petals advertising the location of these food resources for pollinators, the titan arum produces a scent similar to the odor of rotting flesh. This smell—along with the visual cue provided by the bright carmine, open-flesh color of the spadix —attracts (and fools) the carrion-feeding flies, sweat bees, and carrion beetles that pollinate this plant.
What produces the strong odor of this inflorescence?
Research has determined that the chemicals that produce the foul odors emitted by the titan arum inflorescence are the sulfur-containing compounds dimethyl trisulfide and dimethyl disulfide, along with trimethylamine and isovaleric acid. Dimethyl trisulfide resembles the smell of rotting cabbage or rotting onions. Perhaps less odoriferous to humans is dimethyl disulfide, which is described as having a garlic-like smell. Trimethylamine is responsible for the rank odor of rotting fish and marine animals, while isovaleric acid is best described as smelling like sweaty gym socks. All together a pungent combination of chemicals!
Why is the titan arum inflorescence so gigantic?
Because the titan arum inflorescence utilizes odor to attract its pollinators, its giant size allows it to stand out and its scent to spread over a greater distance in its dense tropical jungle habitat. The inflorescence can grow 8 to 10 feet (3 meters) in height.
How long will the inflorescence last?
Though difficult to predict, the inflorescence and its scents last between 24 and 48 hours from beginning to finish. After flowering, it will continue producing a leaf each year to store the energy required to produce another inflorescence. This cycle continues over the approximate 40-year lifespan of the plant.
Do any other strategies help the titan arum attract pollinators?
The titan arum employs thermogenesis, which is a fascinating biochemical process of heat production in plants. In the cells of the inflorescence energy is used to increase its temperature during flowering, which helps the chemical compounds to volatilize more readily and for pollinators to mistake the red spadix for animal flesh. This evolutionary adaptation has evolved many times and allows the spathe and spadix of our native skunk cabbage to melt their way through the snow in the late winter to get a head start on reproduction when its pollinators—scavenging flies and beetles—are emerging from dormancy.
How does pollination occur in the titan arum inflorescence?
The spadix of the titan arum includes both female and male flowers, which open at different times to help ensure that plant does not self-pollinate. Opening first are the female flowers, which are red and located at the bottom of the spadix. Male flowers open later and are located higher up on the spadix. When pollinators fly to another corpse flower, they start again at the bottom and fertilize the female flowers with the pollen it collected from another titan arum.
Does the titan arum have leaves?
The titan arum produces a single leaf annually over the course of several years, which is small at first and gets larger each time. Though it can grow to 15 feet in height and look like a small tree, the structure is, botanically speaking, a single enormous leaf. Photosynthesis in the leaf allows the titan arum to store energy in its underground corm, a kind of underground stem that stores nutrients. Seven to 10 years of leaf production may be required to reserve enough energy for the corm to emerge and develop the inflorescence.
Where do the titan arum fruits develop?
If pollination of a titan arum is successful, a cylinder of small fruits develops at the base of the spadix. The marble-sized fruits are eaten and dispersed by tropical birds that excrete the inner seeds after enjoying their fleshy covering.
What will happen to this plant when the bloom cycle is complete?
After this event, this particular plant will enter dormancy. Perhaps after several leaf cycles over several years it will have reserved enough energy to flower again.
Why is the titan arum so rare?
There are many reasons that a plant may be rare in the wild. This may include requirements for extremely specific cultural needs or environmental conditions to survive and reproduce, population isolation, or specific mutualistic relationships with other organisms like pollinators. While some combination of these factors may contribute to the titan arum’s rarity, it faces the additional threats of over collection as well as deforestation in its natural habitat.
Why is the Arboretum growing a corpse plant?
Amorphophallus titanum are just one of a number of foul-smelling, fly-pollinated flowers growing in the botanical teaching collection in the Weld Hill Research Building, but the corpse plant stands out for its size, pungency, and rarity. These endangered plants are estimated to have less than 1,000 remaining in the wild. Specimens in cultivation are well tracked by botanic gardens as part of a conservation project headed by Chicago Botanic Garden. The goal of the project is to identify and create a database of the genetic makeup of A. titanum plants currently in botanic garden collections. The information is used to ensure a broadening of the gene pool by creating diversity amongst new offspring through cross-pollination of diverse parent plants.
What is the name of the Arboretum’s corpse plant?
This plant has been affectionately named “Dame Judi Stench” by Arboretum staff. Since each of the titan arums held in botanical collections is genetically important and distinct, many gardens track them by name rather that ID number. For example, Fester, Spike, Sprout, Alice the Amorphophallus, Whiff, and Musky are nationally known and followed corpse plants. The Arboretum’s botanical teaching collection features two Amorphophallus titanum plants gifted by Ohio State University as offspring of their plants, “Woody” and “Maudine.” Seeds for these plants were started on April 16, 2013, and staff have since cared for these plants through multiple vegetative and dormancy stages. In April of this year, we suspected one might be entering a bloom cycle, and so “Dame Judi Stench” and “Pepe le Pew” were selected by popular vote as names for the two plants. We have not yet seen an inflorescence from Pepe le Pew, so perhaps this plant will surprise us with a bloom cycle next year!