Our Changing World: Helping New Zealand’s understated orchids

9:38 am today

Veronika Meduna, for Our Changing World

A close-up of a person's hands holding a Petri dish with brown dried leaves and twiggy looking roots in it. The person is using a red pen to point to a seedling.

Cooper’s orchid seedlings produced in the lab. Photo: Veronika Meduna

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A tiny population of rare native orchids has received a boost with the first-ever reintroduction of lab-grown seedlings into the wild.

Cooper's orchid - New Zealand's rarest and most elusive native orchid species - spends years growing underground, before emerging as a leafless stick with brown flowers.

This subterranean lifestyle, plus a fussy relationship with fungi, makes conserving these orchids particularly challenging.

New Zealand's understated orchids

With more than 25,000 species worldwide, orchids make up one of the oldest and largest families of flowering plants.

They usually produce colourful and showy flowers, but their seeds are very simple - they contain no food reserves and only sprout if they come in contact with the right fungus.

A twiggy orchid with brown and white flowers emerges out of the forest floor. It is marked with a bright coral-coloured ribbon.

The Cooper’s orchid only emerges briefly every few years to push out a stick with drab looking flowers. Photo: Carlos Lehnebach

New Zealand's native orchids are no different when it comes to their dependence on fungi, but they are much more modest, even drab-looking, plants.

Cooper's orchid is a species of potato orchid or Gastrodia. This group takes modesty to the extreme. They spend years underground growing as tubers, much like dahlias or kūmara. When they emerge briefly to produce a flower, all you can see is a brown and leafless stick.

Despite their understated looks, New Zealand's less flamboyant orchids caught the attention of botanist Dr Carlos Lehnebach, who moved from Chile to study their ecology.

Carlos, botany curator at Te Papa Tongarewa, scientifically described a new potato orchid species in 2016, naming it after botanist and orchid lover Dorothy Cooper.

At the time of its identification, there were only three known populations of Cooper's orchids: two in Nelson and one in the Wairarapa, numbering no more than 250 individuals in total. A handful of observations scattered around the country have since been reported.

Two women and one man sitting in front of bush-clad hills beneath a grey sky. All three are smiling.

Orchid conservation scientists. From left: Jennifer Alderton-Moss, Dr Karin van der Walt and Dr Carlos Lehnebach. Photo: Kathy Ombler

A conservation challenge

In an effort to save the Cooper's orchid, Carlos teamed up with plant conservation researchers Dr Karin van der Walt and Jennifer Alderton-Moss at Ōtari-Wilton's Bush, New Zealand's only botanic gardens dedicated to native plants.

The trio of botanists hoped to sprout Cooper's orchids in the laboratory - a feat far more complicated than tending to many other plants.

Even though the tubers of more common Gastrodia species are harvested in some countries for medicinal use and food, there's still a "massive knowledge gap" about their ecology, says Karin.

"The challenge for us when we work with these really rare species is that it's almost like the ambulance is reaching the bottom of the cliff already and we've got this mountain of information to figure out before we can effectively conserve this species or prevent extinction."

In particular, the species' underground lifestyle and mandatory relationship with a very specific type of fungus proved tricky.

A tan coloured bundle of tiny knobbly roots in the shape of a star, covered with a thin film of white fungi.

This alien looking thing is a Cooper’s orchid seedling. Like all orchids, this rare native species needs a fungus to sprout a new seedling and this one was produced in a Petri dish by mixing orchid seeds and different soil fungi. Photo: Jennifer Alderton-Moss

Lab-grown seedlings return to the wild

It took years to identify the right fungus, extracted from tubers of a much more common potato orchid.

Eventually the team succeeded in developing in vitro techniques to grow enough healthy Cooper's orchid seedling to start returning them back to wild.

The team planted 14 of these seedlings at the Wairarapa site where they first collected seed.

Three people in dense bush. A man on the left is crouching in the undergrowth, a woman in the middle is bending over with a notebook and pen and a woman on the right is holding a camera.

The orchid team is reintroducing Cooper’s orchid seedlings they grew in the lab back into the wild. Photo: Veronika Meduna

Carlos expects it could be some time before they can tell how well they are doing, but having a method to propagate orchids in the lab provides an insurance policy.

"If something bad happens that wipes out a population, we will have a backup that can help us to reintroduce the species back to the wild."

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