This fungus feeds on wood and forms its edible mushrooms mostly on different kinds of fallen wood such as tawa and tawai or at the base of dead trees.
It appears in late autumn to early winter and can often be collected in large numbers throughout Aotearoa. Its white mycelium may be seen under the bark of affected wood as the wood rots. It also forms black bootlace-like cords under the bark and growing out through soil and can use these to grow to a new source of food.
Recent records indicate that some Tūhoe continue to collect this as a food in Te Urewera. Maybe this mushroom could also be cultivated on logs or sawdust as a wild food?
There is more than one species of Armillaria in Aotearoa, and at least some, such as Armillaria limonea, are bitter in taste and not edible. Distinguishing words in te reo Māori for these fungi of similar appearance but inferior use are not known.
The word harore is used in three senses – it is the name of this widely eaten edible mushroom, it is commonly used as a generic word for mushrooms whether edible or not and it can also mean a generic term for fungi in science classification (though hekaheka is the standard word for this purpose).
The weak glow of harore (known as bioluminescence) was discovered in 2015 by a photographer who travels the world photographing fungi. But did our ancestors know this already? Wood decayed by harore sometimes glows at night because the hyphae of harore can be bioluminescent. Bioluminescent mushrooms, however, have not been recorded for any other species of Armillaria elsewhere in the world, so this discovery in Aotearoa was unexpected.
IMAGE: The mushroom Armillaria limonea that lives on wood, here photographed using a flashlight and in darkness using its own light (bioluminescence). Taylor Lockwood.