BOTANISTS FROM THE Royal Botanic Gardens, Kew and the Netherlands Centre for Biodiversity Naturalis have described the first night-flowering orchid known to science.

The discovery, which was made in New Britain, is published in the Botanical Journal of the Linnean Society.

The new night flowering species, Bulbophyllum nocturnum, is the first known example of an orchid species with flowers that consistently open after dark and close in the morning. Its flowers last one night only.

A relatively small number of plant species have flowers that open at night and close during the day. Until now, no orchids were known among them.

This in spite of the fact that many orchids are pollinated by moths. But these moth-pollinated orchids all have flowers that remain open during the day, even if they are mainly pollinated after dark.

Bulbophyllum nocturnum was discovered by Dutch orchid specialist Ed de Vogel on a field trip to New Britain, where he was allowed to collect some orchids in a logging area for cultivation in the Netherlands.

Under the care of garden manager Art Vogel one of these plant soon produced buds. Their opening was eagerly anticipated as de Vogel and his colleagues had already established that this plant was a member of the Epicrianthes group of orchids that contains many rare and bizarre species, most of which have only been discovered recently as they occur in some of the remotest jungle habitats on earth.

Frustratingly, however, the buds all withered once they had seemingly reached the size at which they should open. Wanting to get to the bottom of this, de Vogel took the plant home with him one evening in order to find out exactly what happened to the buds.

To his surprise, the bud that was then present opened up at ten in the evening, long after dark, revealing the flower of an undescribed species.

Observations on subsequent buds confirmed that they all opened around 10pm, and closed the next morning around 10am. The flowers lasted only one night, which explained why the buds were seemingly about to open one day and withered the next.

Why Bulbophyllum nocturnum has adopted a night flowering habit is unknown and requires further investigation however it is believed that its pollinators are midges that forage at night.

Source: Garden News, 21 November