Botanists rediscover extinct ferns on remote Queensland

The enigmatic filmy fern Hymenophyllum whitei was only known by a single collection in 1931 by Cyril White from Thornton Peak, which rises above the Daintree Rainforest to a height of 1374 metres.

Botanist from the Royal Botanic Garden Sydney Dr Matt Renner was a part of an expedition with the Australian Tropical Herbarium tasked with trying to find the ferns.  

“Hymenophyllum whitei is extremely hard to spot as its fronds are only three centimetres long and when dry they actively hide by curling up and retreating into surrounding mosses and liverworts” said Dr Renner. 

“Ideally, you’d climb Thornton Peak during a spell of dry weather, but that’s when Hymenophyllum whitei is hardest to find.

“Our expedition dates were fixed and due to some rain, we were able to spot Hymenophyllum whitei growing on a boulder on the side of the track on our way to Thornton Peak’s summit.

“At first we struggled to convince ourselves that ‘this was it’, but upon closer examination, we knew it couldn’t be anything else, so we allowed ourselves to get completely ecstatic about it,” Dr Renner said.

The equally mysterious strap fern Oreogrammitis leonardii was only known by a single collection in 1948 by Len Brass on another remote north-east Queensland mountain, Mt Finnigan.

Dr Renner’s chances of spotting Oreogrammitis leonardii were slightly increased as the fern grows to nine centimetres long and is covered in distinctive whitish to pale reddish-brown hairs.

“We made some collections of ferns from a tree trunk that fit the description, but it wasn’t until we were back in Cairns that Dr Barbara Parris, who described the species, confirmed we had rediscovered Oreogrammitis leonardii,” said Dr Renner.

The rediscovery of the extinct ferns would not have been possible without the invaluable preserved specimens kept in herbaria around the world, such as the National Herbarium of NSW at the Australian Botanic Garden Mount Annan.

The rediscovered Hymenophyllum​ whitei and Oreogrammitis leonardii were among 11 ferns presumed to be extinct or missing from the Wet Tropics. 

The flora survey to locate the missing ferns is an ongoing collaborative effort between the Royal Botanic Garden Sydney, Queensland Herbarium and Australian Tropical Herbarium.

Dr Renner will head back into the field to Bellenden Ker later this year with the team led by Dr Ashley Field from the Australian Tropical Herbarium to retrace the footsteps of botanist Karel Domin to try and find the remaining lost ferns.