World's smelliest flower bears fruit

The seeds produced by the "corpse flower" at the Huntington Botanical Gardens, California, US, are believed to be the first produced by self-pollination.

"I felt it would be a miracle if the self-pollination experiment worked. But it did, and it's a botanical first," said Kathy Musial, curator of plant collections. The flower, Amorphophallus titanum, is native to the equatorial rainforests of Sumatra.

It can tower to a height of up to 1.8 metres (six feet) and its smell is also exceptional. The foul odour mimics the scent of rotting flesh in order to attract the carrion beetles that pollinate it.

The plant is rare and threatened by loss of habitat, but propagation is made difficult by the cycle of fertility the plant follows.

A trick of timing

The plant is in bloom for only two or three days, during which pollination must occur. But because the female flowers mature first and are no longer receptive by the time the pollen-bearing male flowers open, the species is not naturally self-fertile.

In the wild, pollen from a second plant in bloom nearby would fertilise the flowers. However, a flowering of this species is extremely rare in cultivation, and so human intervention is required.

John Trager, curator of the Huntington's desert collection frequently hand-pollinates succulents and last summer helped the team to remove several pollen-bearing anthers before maturation. Attempts were then made to hasten the pollen ripening.

One of the techniques involved using a bag of rotting apples, where the ethylene gas produced by the fruit accelerated the ripening of the pollen.

The extracted pollen samples were then applied to the receptive female flowers over the course of 14 hours. During the autumn, round orange fruit began to develop. Dissection of a few unripe samples revealed only pulp and no developing seed. However, when the botanists opened the fully mature fruit, they found almond-sized seeds inside.

"It's the horticultural equivalent of Dolly the cloned lamb," said Mr Trager. "It's very rewarding to be able to propagate a plant which is endangered in nature by habitat destruction."

It is not known whether the Huntington's corpse flower will bloom again but its seeds will be propagated and a new generation of plants will be grown.