As my husband and I were hiking on Sunday, we came across a beautiful little fungus along the trail. Pebbly orange caps with a honeycomb underside. I was enchanted—they were storybook mushrooms that would have nestled neatly into any fairy tale.

But when my husband posted the sighting to NatureWatch NZ, the dirty truth came out.

These storybook fungi are Favolaschia calocera, the orange pore fungus, an invasive weed, and our sighting was the first in Hinewai Reserve.

The orange pore fungus is a curious organism. It appears to be native to Madagascar, though there is some speculation that it might also be native in parts of Asia.

It was first recorded in New Zealand in 1969, and has since spread throughout the North Island and much of the South Island. It has also recently been found in Australia, Thailand, China, Kenya, Reunion Island, and Norfolk Island. Its success probably shouldn’t be surprising—it’s a generalist, invading just about any dead wood available, unlike many other species that have specific tastes. It is also able to produce spores without mating, so it’s very quick to reproduce. It is so successful in New Zealand that mycologists are concerned that it could be displacing native fungi.

But it hasn’t stopped in New Zealand. In 1999, the orange pore fungus was first noted in Italy near the busy port of Genoa. Genetic studies of the Italian fungus indicate that it probably came from New Zealand on imported timber.

This storybook fungus is straight out of a fairy tale, all right—but the tale was written by the brothers Grimm.