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13 Aug 2018

Botany, bryophtyes and a bizarre discovery

Despite being among the first types of land plants to appear on Earth about 470 million years ago, liverworts are easy to overlook. Unless you're Dr Matt Renner, a botanist studying these tiny, ancient land plants for the last 18 years who spotted a new species growing in an unexpected place... 

What are liverworts? 

Liverworts belong to a group of simple plants called bryophytes, which are responsible for causing a major rise in the oxygen content of our planet’s atmosphere, paving the way for complex life and our very existence.

They are generally associated with wet, ‘mossy’ and cloud covered forests, where they hang dripping from trees or form deep, soft turfs over rocks and soil. 

The field trip that sparked the discovery

Dr Renner often ventures into the Australian wilderness with fellow botanist, Dr Trevor Wilson, for up to five weeks at a time to collect and study our unique flora.

The pair went to Jardine River National Park in Far North Queensland in 2014 to search for Plectranthus, an entirely different kind plant from the mint family that thrives in low-lying, dry and rocky habitats.  

“However, something with a particularly familiar bright, yellow-green colour caught my eye growing next to a small waterfall,” Dr Renner said.

“There are around 7500 liverwort species, but never in my wildest dreams did I expect to see one growing here,” said Dr Renner.  

Hand lens, Geneva and a new name 

A botanist never leaves home without their hand lens, however, not expecting to see any liverworts, Dr Renner left his in the car.  

“I borrowed Dr Wilson’s lower magnitude lens, but it wasn’t possible to put the plant into a genus in the field, which doesn’t happen very often,” said Dr Renner.

Frustrated and nearly 700 kilometres from the nearest microscope, the pair took samples of the curious plant to identify it at the Royal Botanic Garden Sydney.

 “Back in Sydney, we established that it belonged to the genus Acromastigum, but it didn’t quite match any species in the published literature,” Dr Renner said. 

By chance, Dr Renner had a trip planned to the Conservatory and Botanic Gardens of Geneva in 2016, which houses the world’s largest collection of liverwort type specimens.

“After comparing our plant from Far North Queensland with Acromastigum type specimens kept in Geneva, we were confident we had discovered a new species.

“It has probably survived in the dry habitat due to a constant splash from nearby waterfalls,” said Dr Renner.  

Every year scientists discover about 2000 new plant species and naming them is the first step in understanding their relationship to other species, creating a conservation plan or investigating their medicinal qualities.

“We named our surprise discovery Acromastigum carcinum, referencing the claw-like appearance of the leaf apex and the Greek word for crab,” Dr Renner said.

Every discovery made has an impact on the greater sum of knowledge, if we don’t know what’s out there we can’t even begin to think of how to use it. 
Dr Matt Renner, Botanist from the Royal Botanic Garden Sydney.

A second surprise discovery 

The trip to Geneva also uncovered that another Australian liverwort species had been mistakenly named after a species from Java, Acromastigum echinatiforme.      

Dr Renner and Dr Wilson renamed the species Acromastigum implexum and published its description along with Acromastigum carcinum in the Royal Botanic Garden Sydney’s Telopea journal.

Listen to the latest episode of Branch Out 

Join Dr Renner and Dr Wilson as they recount their exciting discovery and the fascinating field of botany in the podcast episode below. If you like the show, subscribe to Branch Out and give it a five-star rating and a positive review. 

Science Week activities  

Dr Renner is also part of the Gondwana Garden Family Day at the Blue Mountains Botanic Garden on Saturday 18 August for Science Week 2018. Discover the curious world of bryophytes with Dr Renner as he brings their intricate beauty under the microscope to life.

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