A NIGHT-flowering orchid, the first
of its kind known to science, has been described by a team of European botanists
in Papua New Guinea.
The Bulbophyllum nocturnum is the
first orchid species, out of about 25,000, to only flower at night
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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, BBC News reports this week.
The plant was discovered by a Dutch
researcher during an expedition to West New Britain
province.
The findings have been published in
the Botanical Journal of the Linnean Society.
“It was so unexpected because there
are so many species of orchids and not one was known (to flower) at night only,”
said co-author Andre Schuiteman, senior researcher and an orchid expert at the
Royal Botanic Gardens, Kew,
England.
“It was quite remarkable to find
one, after so many years of orchid research, that is night-flowering,” he told
BBC News.
The specimen was discovered by
co-author orchid specialist Ed de Vogel during a field trip in a region of
lowland rainforest in the province although the exact local was not disclosed.
Its unique flowering behaviour only
came to light after the specimen was taken back to the Netherlands, said
BBC News.
Dr de Vogel had
gathered some of the plants from trees and returned home to cultivate the
orchids at the Hortus Botanicus in Leiden. Most orchids are epiphytes, which
mean they take root on trees.
The botanist
was particularly eager to see the orchid’s flowers because it was a member of
the Epicrianthes group of orchids. This group contains many rare species that
have bizarre flowers with strange appendages, which often resemble leggy
insects, small hairy spiders or intricate sea-creatures
The appendages
are usually attached by thin filaments, which allow them to move erratically in
the slightest breeze. Many have only been discovered
recently as they occur in some of the remotest jungle habitats on earth.
As de Vogel cultivated the orchids, he noticed flower buds appear but instead of opening to reveal their petals, they simply shrivelled up and died.
As de Vogel cultivated the orchids, he noticed flower buds appear but instead of opening to reveal their petals, they simply shrivelled up and died.
He finally
realised what was happening when he took one of the plants home and saw its
flowers open around 10pm one night and close again soon 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.
Flowers that
open only at night are seen in a small number of plant species, such as the
queen of the night cactus, the midnight horror tree and night blooming jasmine.
Bulbophyllum nocturnum is the only orchid among 25,000 species that is
known to do so. Many orchids are pollinated by moths and other nocturnal
insects, but have flowers that remain open during the day.
The specimen has been identified as
belonging to the Bulbophyllum genus, which – 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, B. nocturnum is the first known
species that exclusively flowers at night.
The small
orchid has yellow-green sepals that unfurl to reveal tiny petals adorned with
dangling, greyish, thick and thin appendages. The flower, which is 2cm wide,
has no noticeable smell, though some nocturnal species can time the release of
their scents to attract night time pollinating insects.
Writing in the
journal, the authors point out the striking resemblance between the flowers'
appendages and the fruiting bodies of certain slime moulds found in the same
part of the world. The similarity led the botanists to speculate that the
orchids might be pollinated by midges that normally feed on slime moulds or
small fungi.
Schuiteman said it still remained a
mystery why the plant had developed such behaviour.
“We think related species are
pollinated by tiny flies that think they are visiting fungi,” he explained.
“The flowers mimic fungi, that’s
what the details of the flowers look like they do.
“The flies are looking for somewhere
to lay eggs, and it is most probably (a species) that forages at night.”
He added: “The orchid probably has a
smell, not detectable by humans, to attract insects from a distance – and when
they are nearby, the shape and physical aspects of the flower probably play a
role too.
Schuiteman said the exact reason why
B. nocturnum only flowered at night would remain a mystery until further
field studies had been completed.
However, time may be against them as
the location in West New Britain where the
original specimen was found lay within a logging area.
“It was previously inaccessible but
now the area has been opened by logging,” Schuiteman said, adding that was an
area that needed to be explored because there were probably many more species
waiting to be described.
He said the logging activity was a
double-edged sword because the Papua
New Guinea government had granted logging
licences in the area meant that it created roads that had allowed the plant
hunters to carry out their exploration, yet it was an activity that could
threaten the long-term survival of the species.
“My colleague who discovered it got
permission from the logging company to go into the area, they even gave him a
car to use.
“They realised that it would have
been a shame to log the trees and destroy the orchids because they would be
left lying on the ground exposed to full sunlight.”
He called for areas to be left
untouched: “It is the government that gives permits to log a particular area,
so we should be asking them to protect areas and not issue permits for
everything.”Schuiteman
said: “This is another reminder that surprising discoveries can still be made.
But it is a race against time to find species like this that only occur in
primeval tropical forests. As we all know, such forests are disappearing fast.”
Botanists at
Kew Gardens hope to get a cutting from the orchid in Leiden to cultivate within
the next few years. A specimen preserved in alcohol is already held at the site’s
herbarium.
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