The exotic bloom of the Bulbophyllum nocturnum.
Credit: Jaap Vermeulen.
A "nocturnal" orchid that blooms only under the cover of darkness has been discovered on a tropical island in the South Pacific — a first for the orchid world, scientists say.
The new night-flowering species, Bulbophyllum nocturnum, was described by researchers from the Royal Botanic Gardens, Kew, in England, and the Center for Biodiversity Naturalis in the Netherlands.
Dutch researcher Ed de Vogel collected specimens of the mysterious plant from a logging site while conducting fieldwork in New Britain, a large, volcanic island that is part of Papua New Guinea.
However, the plant's surprising nighttime habits weren't discovered until much later.
De Vogel and his colleagues cultivated the plants back in the Netherlands, and the orchids appeared to thrive in their new greenhouse home. Soon, one plant produced buds.
The researchers had established the orchids belonged to a particularly rare and bizarre group of the genus Bulbophyllum, and eagerly awaited the strange showing that would surely come when the plant bloomed.
However, much to the researchers' disappointment, the buds withered and died without opening.
Perplexed, de Vogel took a plant home with him one evening. Two hours before midnight, a bud began to open, revealing an exotic bloom as yet unknown to science.
Subsequent observations revealed that the other orchids bloomed at 10 p.m. and, the next morning, about 12 hours later, the flowers withered and died.
Other plant species bloom at night — the aptly named corpse flower, whose massive bloom stinks of rotting flesh, typically begins its malodorous display around midnight. Yet once opened, the plant stays that way for about a day.
In addition, other plant species, such as the queen of the night cactus (Selenicereus grandiflorus) and the midnight horror tree (Oroxylum indicum) open in the dark and close shortly before or after sunrise.
However, the newly identified Bulbophyllum nocturnum is the only orchid known to open at night and close when daylight returns.
It's not clear why the plant flowers in the dark, and researchers say more investigation is needed. However, the scientists said it could be that midge flies that forage at night pollinate the orchids.
The discovery is published in the Botanical Journal of the Linnean Society.