SPECIES OF THE MONTH: DECEMBER 2011

NIGHT-FLOWERING ORCHID 

Division   :Angiosperms

Class      :Monocots

Order      :Asparagales

Family    :Orchidaceae

Genus     :Bulbophyllum

Species   :Bulbophyllum nocturnum

A night-flowering orchid, the first of its kind known to science, has been described by a team of botanists. Experts say the "remarkable" species is the only orchid known to consistently flower at night, but why it has adopted this behaviour remains a mystery. The plant was discovered by Ed de Vogel during during an expedition to New Britain, an island near Papua New Guinea, in a region of lowland rainforest on the Pacific island.The specimen has been identified as belonging to the Bulbophyllum nocturnum. The findings appear in the Botanical Journal of the Linnean Society. The discoverer is the co-author the publication.

Its unique flowering behaviour only came to light after the specimen was taken back to the Netherlands. Dr de Vogel took the plant home in an attempt to understand why its buds appeared to wither when they reached a size that would normally produce 2cm flowers.To his surprise, he observed the flowers open a few hours after dusk and remain open until a few hours after sunrise. The flowers opened for one night only, explaining why the buds appeared to be preparing to open one day, yet be withered the next day. The Bulbophyllum genus with about 2,000 species - is the largest group in the orchid family.While there are a number of orchids that do attract night-time pollinators, Bulbophyllum nocturnumis the first known species that exclusively flowers at night.

Although the tiny Bulbophyllum nocturnum is the first known night-flowering orchid, it is not uncommon for plants to flower at night. Most orchids though, flower both day and night.The most famous night-flowering plant is the queen of the night cactus (Selenicereus grandiflorus). Each individual dinner plate-sized flower opens for one night per year (although each cactus can have several flowers). It is not clear exactly what pollinates Bulbophyllum nocturnum, but scientists think the job is carried out by nocturnal flies. Many night-flowering orchids are strongly scented in order to attract moths, but this orchid is the wrong shape and size for that.  

Courtesy: BBC News