Foraging for wild food is a way to enjoy time outside, connect with nature – and come home with some fresh edibles to supplement our diet.

But we do need to take care.

Know what to look for, and you can sustainably gather free food from your neighbourhood or local bush. Make a mistake, and you might end up with diarrhoea, in hospital or dead.

Dandelion, chickweed and miner's lettuce are all common edible weeds you can find with a bit of hunting.

Fennel and nasturtium are plants that grow in gardens but can often spread to vacant sections and other undeveloped pockets. They all can be used to add colour, texture and tastiness to meals.

Autumn is wild mushroom season. Provided you have the landowner's permission and given the right weather conditions, you can find edible field mushrooms dotted across farmland. Hunt in the bush you might even find edible native mushrooms in the wild.

You could also find the world's most poisonous mushroom.

Amanita phalloides, or the 'death cap”, as it is commonly known, is responsible for more than 90 per cent of world's mushroom-related fatalities.

The death cap's peak season is March to July, says Liv Sisson, Ōtautahi-based forager and author of the just published, Fungi of Aotearoa: A Curious Forager's Field Guide.

Sisson records that the deadly species has been found in the Auckland, Bay of Plenty, Waikato regions in the North Island and in the Nelson and Tasman regions of the South Island. But it may grow in other areas as well.

'When you're foraging for edible fungi, or any other wild kai, you always need to get a positive identification before you eat it,” says Sisson.

Native to Europe, where it is widespread, the death cap is thought to have arrived in New Zealand and Australia along with early oak seedlings.

It is a mycorrhizal fungus, which means it grows in a symbiotic association with the tree roots – though they can pop up some distance from the tree.

Urban forgaging of fennel with Helen Lehndoff along the Manawatu River walking trail. Photo: Warwick Smith/Stuff.

New Zealand's National Poisons Centre advises that when young, the death cap may be mistaken for a small puffball.

As they just begin to open, they can look like the Asian straw mushroom (Volvariella volvacea), and other common Asian edible varieties.

In 2005, a recent arrival to New Zealand became critically ill and required a liver transplant, after eating some cooked death cap mushrooms.

Just one cap is enough to kill an adult, and one bite, a child, the centre warns.

Symptoms of poisoning appear 6-24 hours after eating, with a day or so of violent vomiting, diarrhoea, and stomach cramps.

This is followed by lowered blood pressure, accelerated pulse and dehydration followed by an apparent recovery.

But by this time irreparable, and often fatal, liver damage can have occurred.

In 2020, a Waikato public health doctor nearly died after cooking and eating some death cap mushrooms gathered near an oak tree, during a long weekend in Raglan.

A page from a New Zealand's National Poisons Centre pamphlet.

Mushroom poisoning is the main cause of mortality in food poisoning incidents worldwide. In China, almost 40,000 toxic mushroom related illnesses and 788 deaths were reported between 2010–2020, the University of Sydney reports.

The main toxin produced by the death cap mushrooms is called α-amanitin. Despite its lethal effects, no specific antidote for this deadly poison is currently available, though Australian and international scientists think they may have found one.

When tested on human cells and mice exposed to the death cap toxin, the newly developed drug acted as an antidote, blocking its toxic effects and helping the animals survive. The scientists say more work is needed to assess its safety for use in humans.

Meanwhile, there's plenty of food still available for foragers. As Sisson says, an understanding of what to look for, what to watch out for and plenty of patience will help keep you out of trouble.

Fungi of Aotearoa: A Curious Forager's Field Guide, is published by Penguin Random House, May 2023.

-Sarah Heeringa/Stuff.