Look closer

The lost world in our forest

In this extract from his new book The Forgotten Forest, Auckland Museum’s natural science curator Robert Vennell. takes readers on an odyssey through the ancient world of NZ’s plants and fungi.

Hidden in the dark corners of the New Zealand bush is a lost world waiting to be discovered. A forgotten forest, full of tiny creatures that carpet the ground, drape over branches and logs, and thread their way through the soil.

Most of the time this world remains invisible, disappearing into the green blur of the bush. But take a closer look, and you will uncover some of the most remarkable organisms found anywhere on Earth.

There are glow-in-the dark fungi that grow to half the size of a rugby field, and lichens that have been alive since before the first people arrived here. Giant mosses so tall they look like little pine trees, and intelligent slime moulds that move through the forest in search of prey.

And that’s not all. Although these species have often been forgotten, they have had a surprisingly large impact on our history and lives. They have provided us with food, fire, tools and medicines.

They have served as inspiration for artworks, songs, religion and spirituality. Today, research into these species is leading to breakthroughs in fields as diverse as biology, medicine, engineering, computer science and psychotherapy.

If we can catch a glimpse of this hidden world, it opens up an endless universe of discovery. Suddenly the forest comes alive with wonder, and a simple bush walk will never be the same again.

In this book we will embark on a botanical odyssey to explore the forgotten forest and uncover these incredible creatures and their stories. We will tramp through dense bush, cross steep valleys and hike over mountains, meandering as the mood takes us, between mosses and mushrooms, lichens and liverworts.

Hopefully, as we walk along the trail, this hidden world will slowly reveal itself to us, like the invisible threads of a spiderweb suddenly illuminated by the morning sun.

Few paths in New Zealand will take in all the habitats and species described on our walk in a single day, so this will be a voyage of the imagination. My hope is it will inspire you to look more closely, wherever you are in the forests of Aotearoa and beyond.

I hope you enjoy the journey.

The journey begins

We will embark on our journey early in the morning, leaving with the first light of dawn. We hastily pack our bags with supplies, pull on our boots and step out the door, with no idea where the path might sweep us off to. The trail winds back and forth like a meandering river, slowly taking us out beyond the city limits.

Ahead, dark clouds loom on the horizon, and a wall of grey mist descends, covering the landscape in a blanket of rain. Thankfully, these conditions couldn’t be more perfect. While the forgotten forest can be seen at other times, it is at its most brilliant after rainfall.

Showered with water, its colours become richer and more vibrant as its inhabitants begin to drink, feed and reproduce. Fungi absorb water from the soil and burst forth in a flush of mushrooms. Curtains of moss and liverworts drink moisture from the misty air, swelling until they become delicate, dripping waterfalls.

Lichens begin to emerge from a state of suspended animation, their photosynthetic machinery kicking back into gear. Slime moulds seem to wake from the dead, rousing out of hibernation and moving about the mossy undergrowth.

As the wall of rain drifts off into the distance, we arrive at the edge of the forest. It’s marked by a dense wall of trees, their branches stretching out to form a twisted canopy as they fight for prime position in the sun.

Beneath them, shrubs and ferns grow over one another in a messy tangle, competing for the scraps of light that fall through the foliage above. Somewhere among this chaotic menagerie of plants are the creatures we are searching for. We take a quick breath and plunge forward into the unknown.

The mystery of mushrooms

As we push through the dense wall of tangled vegetation, every branch and vine seems determined to slow us down. We try to navigate the fortress of spiky twigs, and dodge the branches clawing at our clothing and holding us back. Finally we emerge into an open clearing.

A tall tōtara tree, unstable in its old age, has toppled over, smashing open the canopy and allowing the light to flood in. We rest a hand on the mighty trunk, wondering about the long life it must have lived. But while the death of this forest giant is an ending of sorts, for some, it’s a new beginning.

Smaller plants seize the opportunity the tree has created, growing into the light gap and staking their claim to be the next giant of the forest. Suddenly, we spot something that looks out of place. A pale white orb, like a fleshy egg, that is growing out of the disturbed soil and woody debris the tree has uprooted. As our eyes adjust, we spot more of these little eggs scattered throughout the forest clearing.

Without warning, one of them ruptures, and out come clammy, white arms, which slowly inflate and expand, forming a perfect geodesic dome the size of a small soccer ball.

Off to the side, we spy another white dome that has become detached from its fleshy egg, and has started to sag and droop under its own weight. Then, all at once, a gust of wind barrels through the trees, blowing the white dome about the forest like an alien tumbleweed on the surface of another planet.

This is the basket fungus (Ileodictyon cibarium). For Māori, these bizarre fungal fruiting bodies have been seen as marking the presence of the atua (ancestral beings with influence over the natural world).

Some believe these baskets are te kupenga o Taramainuku –the fishing nets of Taramainuku, an atua who casts his nets into the mortal world, capturing souls to bring down to the underworld. Others describe them as tūtae whaitiri, the faeces of Whaitiri, atua of thunder. After the storms of Whaitiri rage, these little white droppings can often be found scattered across the landscape.

Looking a little more closely at one of the baskets, it’s easy to understand the name, as the inside of the arms are smeared with a brown, foul-smelling slime. This unpleasant stench is the creature’s ingenious approach to reproduction. By mimicking the sight and smell of faeces, it lures flies, tempting them to have a closer look. Its sticky spores adhere to their legs, recruiting the flies to disperse their fungal offspring across the forest.

Despite the unpleasant odour, these fungi were once highly regarded as a food source and considered a sweet treat. They were a particular delicacy in Hawke’s Bay, and are said to have given their name to the town of Waipukurau (‘waters of the basket fungus’), where they were taken to a special watering hole in the area to soak before eating. The trick to eating them was to harvest the fruiting body during its early stages, before the white arms have emerged from the volva – the egg-like ball at the base of the fungus.

The volva was peeled away from the basket and cooked either by placing it in the ashes of a fire or steaming it in a hāngī. The soft, jellylike texture of the fungus made it easy on the stomach, and it was a useful food to give to the sick or elderly. The taste somewhat resembles a strange, otherworldly potato, crispy on the outside and gooey in the middle.

Leaving behind this strange, smelly fungus, we carry on with our walk. But, before we can leave the clearing, another ghostly apparition appears. Half-concealed among the leaf litter is what looks like a red hand – like a zombie bursting through the soil, trying to claw its way back to the land of the living. Adding to this impression, the air is thick with the smell of rotting flesh.

Against our better judgement, we pinch our noses and force ourselves closer to discover that this is not a hand, but another strange fungus.

The ‘fingers’ sprawl out into thin tendrils like the tentacles of a sea anemone, and the ‘wrist’ is a hollow tube smeared with a thick, brown slime. This is the starfish fungus or, as scientists know it, Aseroe rubra, which is Latin for ‘disgusting red juice’. Its te reo Māori name – puapua-a-Autahi – tells a story about its place in the environment. It is a pua (blossom) of the star Autahi (Canopus), and particularly his child te kōhī a Autahi, the heavy rains of autumn.

This fungus can be seen emerging from the ground just as te kōhī a Autahi brings a sharp, icy chill to the land. Despite its revolting smell, the starfish fungus was eaten by Māori, harvested during its early growth, before it became too smelly.

However, it was important that this fungus was left to cook for as long as possible, as it is poisonous without proper preparation and can cause its victims to stagger about uncontrollably.

One method of cooking was to wrap them in rangiora leaves and bury them in hot embers for several hours. They must have been valued highly enough to make the risk worthwhile.

Some have experimented with eating this fungus in more recent times, but reviews of the taste are not usually complimentary. Mushroom enthusiast David Arora tasted the closely related octopus stinkhorn fungus and recalls that it left behind ‘a sticky spore mucilage … which clung to our throats and tongues so tenaciously that we were still trying to wash it away several hours later’.

The path beckons and draws us further into the depths of the forest. The trees seem to close in around us, and the light from the outside world slowly fades. As we push on through the dark woods, it is hard to shake an eerie feeling that we are being watched. It’s as if this is sacred ground and someone, or something, is aware of our presence.

With every step, the last few specks of light filtering through the canopy are snuffed out, engulfed by the growing shadow of the trees. Now, our imaginations are running in overdrive, and we begin picturing faces in the dark. Ghostly apparitions seem to appear and disappear at the edge of our vision.

A faint, eerie glow emerges from the darkness, like stars slowly appearing in the night sky. We make for a ghostly blue light in front of us, and realise it is emanating from the rotting wood and soil on the side of the track. This is no ghost, but another otherworldly fungus known as harore (Armillaria novaezelandiae).

Harore is one of a small number of New Zealand mushrooms that glow in the dark. In days gone by, swathes of these glowing fungi produced remarkable displays across the forest, putting out enough light that rotten logs infused with harore could be used to light up a room at night.

Early Pākehā settlers marvelled at these luminescent fungi as they explored New Zealand’s forests. Missionary and botanist William Colenso frequently encountered them in the depths of the forest, where they reminded him of strange demonic faces: ‘The peculiar pale colors of various hues of that strange light, together with the coldness of those gleams … caused an unpleasant unearthly kind of thought and feeling – almost causing one’s flesh to creep.’

Naturalist Ernst Dieffenbach, travelling through the forests of Taranaki after rainfall, remarked that the whole forest ‘sparkles in a thousand places with the phosphorescence of the decayed matter; – we seemed to have entered the illuminated domain of fairy-land’.

Māori often attributed the light of these glowing, wood-decaying fungi to bioluminescent glow worms – and the fungi were particularly associated with the wood of the rewarewa tree.

In some areas there was a tradition that rewarewa timber should not be used to light the fire for a hāngī, for fear it might kill any glow worms inside. This might anger their tupuna Tangaroa – atua of the ocean – and cause him to devastate the kūmara crops in revenge.

The glowing threads of the fungus spread out in front of us, a sprawling, luminescent network. It’s clear that this is a truly humongous fungus. A single individual is believed to grow to roughly half the size of a rugby field, making it one of the largest living creatures in New Zealand.

The glowing fungal threads lead back to their source, a dying tawa tree. The mycelium – the cobweb-like living threads that make up the fungus – reach under the bark of the infected tawa, parasitising its host and draining it of sugar and nutrients. Larger threads of mycelium, like thick bootlaces, sprout out of the bark in search of more food.

Protruding out of the side of the tawa trunk is an eruption of shiny, honey-coloured mushrooms, with a hint of the same faint glow. This is the fruiting body of harore, once one of the most widely eaten mushrooms in New Zealand. Māori would cook them by placing them in big, woven baskets and steaming them in hāngī.

Harore and other large bush mushrooms disappear rapidly, and they needed to be harvested as soon as they were spotted. This gave rise to the whakataukī, ‘he harore rangitahi’ – a one-day mushroom.

The phrase was a way of describing things in life that were transient and impermanent, but also a biting comment used against someone who only shows up to work for a short time and then disappears again.

The almost magical appearance of these large mushrooms in the forest in autumn also served as an important tohu – a sign that could be used to predict changes in the natural world. In some places, an abundance of harore and other bush mushrooms was a tohu that hard times were coming, and that the foods of the forest would soon be sparse, while in other places, a flourishing of harore was a clear indication that it would be a good season for fishing for blue moki.

The Forgotten Forest, published by HarperCollins NZ, is out now. RRP $40.