The titan arum – a rock star of the botanical world.

Yesterday in Auckland there was a long line of people waiting for a glimpse of something special. This wasn’t the queue for a Justin Bieber concert – the star of this show was a plant!

The big attraction was a huge inflorescence of a titan arum (Amorphophallus titanium – the scientific name means giant misshapen phallus) at Auckland Domain’s Wintergarden. This species has the largest unbranched inflorescence in the world (up to 3m tall!). However, flowering is a rare occurrence with plants taking between 7-10 years to first bloom and each inflorescence only lasting for a maximum of 48 hours. Apparently this is the first time this species has flowered in New Zealand.  If you weren’t able to get to Auckland Domain there are fantastic photos on the Auckland Council facebook page and a time-lapse video of the flower opening.  

Amorphophallus titanum in flower, Auckland Domain Wintergarden, 01 December 2013. Photo credit Auckland Council.

Amorphophallus titanum in flower, Auckland Domain Wintergarden, 01 December 2013. Photo credit Auckland Council.

Titan arums are members of the Arum family (which includes the popular houseplant the peace lily). Members of this family typically have an inflorescence structure where a sterile bract called a spathe is wrapped around a central spike (called a spadix) that bears hundreds of small flowers. In the titan arum the female flowers are at the bottom of the spadix and open first. The male flowers, which are higher up the spadix, open later, preventing the flower from pollinating itself.

Why is the titan arum inflorescence so large? Contrary to folklore that their flowers are pollinated by elephants, research has shown that the titan arum is pollinated by carrion beetles and flies. These insects are fooled into thinking that they have landed on a corpse of a large animal. There are several features of the flowers that mimic a corpse:

The dark red spathe is the colour of rotting flesh.

The flowers release chemicals that smell like rotting meat.

The spadix heats up to body temperature (36-38ºC). The increased temperature may also aid in dispersing the putrid smell to reach more pollinators because the chemicals become more volatile when they are heated. This thermal imaging video clearly shows the increased temperature of the flower, relative to its surroundings.

If you would like to grow your own titan arum then you are probably out of luck (unless you have a very large glasshouse). The species originates from the rainforests of Sumatra and requires very warm humid conditions.

Close-up of the base of a titan arum spadix, Auckland Domain Wintergarden, 01 December 2013. Photo credit Auckland Council.

Close-up of the base of a titan arum spadix, Auckland Domain Wintergarden, 01 December 2013. Photo credit Auckland Council.

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