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Unique ‘penis plant’ flowers at Hortus

Amorphophallus decus-silvae, or the ‘penis plant’ as it is known, has just flowered at the Hortus botanicus. It flowered for two days, and then the pollen, which the male flowers produced was collected. As far as the plant experts at the Hortus can tell, this was just the third time that this species has flowered in Europe. The last time a similar plant flowered in the Leiden Hortus was in 1997.

The plant, which was grown by Amorphophallus volunteer Rudmer Postma, is about six years old and is flowering for the first time. The bud was spotted in mid-September and it quickly grew to a two-metre long stem with an inflorescence (flower) of around half a metre. The last time another plant of the same genus flowered at the Hortus was in 1993 and 1997. Very few botanical gardens have Amorphophallus decus-silvae in their collection, which makes it very rare for the plant to flower.

Rotting flesh

The flower’s scent reveals that it is flowering. Amorphophallus decus-silvae flowers in two phases. The first phase is the female one: the spadix (the white, phallic part of the inflorescence) warms up and emits a penetrating smell of rotting flesh. Flies and other pollinators love this smell and arrive en masse. Then it’s time for the male phase: the plant produces pollen, which covers the flies. Once the plant has flowered, the pollen-covered flies head off for their next meal. With any luck this is another Amorphophallus decus-silvae, which they will then pollinate. As there isn’t another Amorphophallus decus-silvae at the Leiden Hortus, the pollen is being collected to use later or send to other botanical gardens.

Amorphophallus decus-silvae is closely related to the better-known Amorphophallus titanum (corpse plant), another crowd pleaser at the Leiden Hortus. Together with the Amorphophallus gigas the three are the giants of the genus and occur naturally in tropical rainforests in Indonesia. Amorphophallus decus-silvae is the only one of the three that only grows on the island of Java. It is difficult to get the plant to flower because it requires specific conditions: a very hot and fairly humid environment. Hortus volunteer Rudmer Postma has managed to coax the plant into doing so.

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