He'd never seen anything like it and found it was a species unknown to science - one of between two and 10 million scientists estimate are still to be discovered.

The 10-year hunt to identify and properly name the mushroom dubbed "frosty blue" is part of a new documentary Axford has made with partner filmmaker Catherine Marciniak called Follow the Rain.

Fungi are the chief decomposers of the world's ecosystems, yet their crucial role in the environment is not widely understood or appreciated.

"The whole planet is just wrapping its head around the fact that without fungi, there would be no forest, there would be no humans," Marciniak says.

She and 72-year-old Axford have travelled the world to discover and document fungi, from Patagonia to China, India and Nepal. Axford even has a mushroom found in China named after him, Panaeolus Axfordii.

His fungi images and films have featured in many documentaries, including David Attenborough's Planet Earth 2, and collected millions of views on YouTube.

On one trip to Myanmar after the 2018/19 mushroom season, the couple were tasked with finding a deadly mushroom that had killed locals who had eaten it.

They managed to identify and photograph the new and toxic mushroom from the group Amanita phalloides, commonly known as the death cap.

With so much unknown about the fungi kingdom (it is distinct from plants and animals, having branched away about a billion years ago) they often make new discoveries closer to their NSW home.

For example, on a hunt for bioluminescent fungi, Axford didn't even have to leave his property near Lennox Head.

He simply switched off all the lights and stepped into his backyard.

"Turned the torch off and there they were," he says.

"Surprisingly, a lot of people here haven't seen them because they've never wandered outside at night with no torch."

The endangered NSW north coast forests are a hotspot for fungi but have never been properly surveyed to find out what species live there, Axford says.

So when the pandemic forced the couple to pause their overseas adventures, they began piecing together Follow the Rain, starring Australian fungi.

It's the film they have always wanted to make, says Marciniak, 65, who hopes it will help audiences understand the wonders of these neglected organisms.

When fires went through the NSW north coast in 2019, firefighters rang to let her know they had spotted mushrooms emerging from the still-smoking ground.

The fireground fungi were spread across the burnt surface, effectively holding the ash down and keeping the soil together.

She jumped at the chance to film these unusual species, which may never emerge above ground until a fire has been through.

"We started doing stuff like that, which was pretty pioneering, and people were really interested, and I guess it just inspired us to keep going," Marciniak says.

When floods hit the region in 2022 she and Axford documented that too, finding even more never-seen-before species after the water receded, as well as rarely spotted mushrooms suddenly in profusion.

Axford has also become an expert in fungi time-lapse films, starting by converting a shower recess into a darkroom to film mushrooms sprouting on rotting logs.

As the operation grew, he began filming in a converted half-size shipping container dubbed "the fungarium", with a short film taking anywhere from one day to a couple of months.

These clips, featured in the documentary, have revealed a wealth of new information for scientists about how fungi actually behave, such as how they respond to heat, light and other organisms.

But taking high-end photography and filmmaking gear into forests can be challenging, Marciniak says.

The title of the film is a hint that it's usually pretty wet but she has become used to filming in the rain, lugging film gear to remote places, and recording sound and vision solo.

"They're really horrible conditions, I think we're a bit mad really," she says.

"But it does mean we get stuff that nobody else gets."

Follow the Rain premieres at Bangalow Film Festival in March.

Australian Associated Press