Foul and fragrant

Pushing our noses into the depths of a rose flower and breathing in deeply has got to be one of life’s pleasures, but not all flower scents are quite as enjoyable. Floral scents are produced to attract pollinators, and while many insects are attracted to the sweet floral scents we are familiar with in our gardens, others are attracted to more unpleasant smells. Some insects are attracted to flesh or dung on which to feed or breed, and these can be tricked into being pollinators by flowers that mimic these unpleasant odours.

Perhaps the most renowned plants for producing foul odours are members of the genus Amorphophallus. There are more than 200 species, occurring throughout Africa and Asia, but the most famous is Amorphophallus titanum (titan arum or corpse flower). When the titan arum flowered at Kew in 1996 for the first time in decades, crowds flocked to the Gardens to experience the sight and smell of this giant bloom. It is now a regular bloomer in the Princess of Wales Conservatory.

Periodic pongers

The rotting smell from the titan arum is mainly produced on a single evening, with just a faint whiff the following evening. Therefore inquisitive titan arum sniffers who visit the plant only during the day may be disappointed.

Many species of Amorphophallus behave in the same way, and trying to predict the evening on which they will perform has complicated attempts to analyse their odours. Our research into the chemical composition of 92 species of Amorphophallus has taken us over 20 years to complete, including countless evenings 'babysitting' glasshouse plants waiting for a pong that often never materialised on the expected evening. The results were recently published in the scientific journal Phytochemistry.