We recently were donated a titan arum from a kind unidentified donor. Kenny had been looking for this species for a long time since we already have its sister species Amorphophallus paenifolious. Actually we were given 2 and one strangely disappeared much to Kenny’s  disappointment as these are extremely rare plants which are only found in one place in the world – Sumatra. We were extremely lucky to have it donated to us. And similarly with the eagle eye care Kenny gave the Victoria amazonica, Im sure he will guard this also – actually its sitting in our office, so it cant be more protected than that. Of course we will give due warning to all our visitors when our titan arum is flowering so we dont knock them all out with foul stenches!

The Amorphophallus titanum or the titan arum is native to the rainforests of central to the western part of Sumatra. It is normally found on elevations between 120 to 365 metres above sea level and it was first discovered there in 1878 by an Italian botanist and explorer by the name of Odoardo Beccari.

An innocuous young shoot of the Amorphophallus titanium

Distinct Features

The two distinct features of this plant is the sheer size of its single unbranched inflorescence, known to be the largest in the world, and the foul odour that it emits. The name Amorphophallus titanum is derived from ancient greek amorphos meaning “without shape or form”, phallos, as in phallic symbol and titan, huge.

Inflorescence & Flowers

The titan arum’s inflorescence rises from a tuber from where it stores its food. This tuber, more or less spherical in shape and can weigh up to 75 kg or more, is the largest such structure known in the plant kingdom. The inflorescence consists of a spathe (collar-like structure) wrapped around a spadix (flower-bearing spike).  It is green speckled with cream on the outside, and rich crimson on the inside. It has ribbed sides and a frilled edge, and in general a rather unusual looking flower. The Amorphophallus paenifolious has flowered in the gardens before and that was quite an oddity too [but without the foul smell!] The flowers are carried on the lower end of the greyish-yellow spadix.

Strange smells!

When the flowers are ready for pollination, the spadix heats up and gives off a nauseating smell. This stench is so bad that the Indonesians call the plant ‘the corpse flower’. It smells like rotting fish – hmmm, yum! Natives in Sumatra locate the flower by smell from up to fifty yards away.It is often so strong one can’t even stand close to it. So of course we invite this plant in ith mixed feelings since I could potentially chase all the garden visitors away! According to a web page at Kew Gardens, Dr Geoffrey Kite was able to trap the odor and determine that the major constituents were dimethyl disulphide and dimethyl trisulphide, two compounds with sickening smells (something like rotting eggs).

Pollination

The foul odour is, presumably, to attract insects that normally feed on dead animals (“carrion”). Carrion-loving insects include many species of flies, carrion beetles, and wasps. While in the flower, the insects carry pollen from one plant to another thus pollinating the flowers. Competition for pollinators is great in tropical regions due to very high diversity. If the flower was successfully pollinated, the surrounding spathe eventually falls off exposing the maturing seeds. When ripe, the seeds turn a bright orange-red, which is probably attractive to birds which pick them off, eating the flesh and discarding the “pit” or seed. In this way, the plant is dispersed. The stench will normally last about a day and the collapse of the spadix takes place after three to five days.