Those visiting the Montréal Botanical Garden’s Orchids and Aroids Greenhouse these days have the opportunity to observe one of the world’s most fascinating plants: titan arum (Amorphophallus titanum). This species is famous for its enormous, suggestively shaped bloom (hence its scientific name) and the foul smell (especially at night) it emits during its brief and unpredictable flowering. Infrequent in cultivation and rarely observed in nature, this is always a special event.
The specimen on display at the Botanical Garden is nearly ready to flower, but we have no way of knowing exactly when this will occur (the photo above is of another specimen, which flowered in the US). It’s a bit like waiting for a birth. It could happen any time!
A vulnerable species
The titan arum belongs to the aroids family, like the anthurium and spathiphyllum, which are often used to decorate our homes. The species is endemic to the tropical rainforests of Sumatra, in the Indonesian archipelago. It was discovered in 1878 by Italian botanist Odoardo Beccari. Facing the threat of deforestation and pillaging, it was classified as a “vulnerable species” on the International Union for Conservation of Nature’s red list in 1997.
A larger-than-life plant
Everything about the titan arum is disproportioned. In the ground, its tuber, the largest of the plant kingdom, can measure more than one meter in diameter and weigh more than 100 kg. From this reserve organ, a single leaf that can reach the size of a small tree emerges, withering after four to six months. The plant then enters dormancy before producing a new leaf. The growth and dormancy cycle continues, with the tuber growing until it has enough energy to produce one of the largest inflorescences in the world. Its inflorescence consists of a spathe (large bract), which surrounds the spadix (spike of flowers). The spathe hides hundreds of tiny male and female flowers at the base of the spadix. In cultivation, the titan arum can take ten to fifteen years to bloom for the first time. Then, in optimal conditions, it can produce an inflorescence about every three years.
The “Corpse Flower”
As the titan arum is about to bloom, its inflorescence grows longer for about two to three weeks. However, the flowering itself is fleeting (48–72 hours) and very hard to predict. Once the spathe is deployed, the spadix releases heat and a strong smell of rotten meat that attracts pollinating insects (e.g. coleoptera and flies) and can be detected several hundred metres away. This “fragrance” is released in the evening and night of the first day of flowering, when the female flowers are receptive to pollination. The smell begins to fade in the morning.
Once the flowering is over, the inflorescence soon withers and the plant once again goes dormant until another leaf appears and the cycle begins again.
The smell of the titan arum is so intense that the Indonesians named it the “corpse flower.” Note, however, that even though many of the 200 Amorphophallus species release nauseating odours, some of them smell of bananas, carrots and even chocolate!
This article was written in cooperation with Catherine Boudreault, horticulturist at the Montréal Botanical Garden.
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