Fertile Feet or Fungi?
Have you ever seen a circle of bright green grass in a field or a ring of mushrooms around a tree? Legends say these rings are left behind by fairy feet after a night of singing and dancing. They are best avoided, for entering a fairy ring will curse a person with bad luck for the rest of their shortened life. But not even black magic can repel a curious biologist.
When it comes to fairy rings, researchers can’t keep away. The first scientific paper on this phenomenon was published in 1675. Scientists originally thought these rings had an electric origin, but it wasn’t long before the true culprit was identified. Fairies! Wait . . . what? Sorry. I mean “fungi.” In the late 1800s, three chemists determined that the luxuriant rings of grass were the result of a fungus growing underground.
It works like this:
Fungi grow underground in a mass of fine, thread-like filaments called hyphae. When a spore lands in a favorable environment, say by a pile of manure or over a buried, decaying tree stump, the spore will germinate to produce hyphae.
The hyphae grows into the organic material, breaking it down for nutrients.
Over time, the fungus grows out radially from its point of origin, creating a circle.
Fairies notice this circle and use it to host a wild dance party.
Eventually, the organic material in the center of the circle is completely broken down. The hyphae there die for lack of food, but the hyphae on the circumference of the circle continue to grow and thrive.
As the fungal ring grows, it releases nitrogen (fertilizer) and often alters the chemistry and microbial composition of the soil in ways that boost plant growth. Some species of fairy ring fungi also release so-called “fairy chemicals” that are modified by plants to produce growth stimulating hormones.
Some fairy rings are free, meaning they are not associated with any other organism. These are the kind that form rings on lawns or pastureland. Others are tethered, meaning that they grow in a symbiotic relationship with the roots of plants. These are the kind that form rings of mushrooms around trees. Many fairy ring fungi are favorable to plant-life, while others are pathogens that can leave behind dead patches of grass. Neither are welcomed on golf courses.
So fear not the curse of the wee people. It was fungi not fairies all along! What a relief.
Brian Rutter, PhD, is the cofounder of Thing in a Pot Productions and a postdoctoral researcher in plant biology at Indiana University. Subscribe to our newsletter to receive our “Things About Things – Odd Facts About Plants” and video production tips in your inbox every month!
Works Cited:
EVERSHED, H. Fairy Rings . Nature 29, 384–385 (1884). https://doi.org/10.1038/029384e0
Kaczmarek, F. Of Fungi and Fairy Rings. northernwoodlands.org. October 25 2021. https://northernwoodlands.org/outside_story/article/fairy-rings
Kawagishi, H. (2018). Fairy chemicals–a candidate for a new family of plant hormones and possibility of practical use in agriculture.Bioscience, Biotechnology, and Biochemistry, 82:5, 752-758, DOI: 10.1080/09168451.2018.1445523
Mason J. THE FOLK-LORE OF BRITISH PLANTS. Dublin University Magazine, 1833-1877. 1874;83(493):63-81. https://proxyiub.uits.iu.edu/login?qurl=https%3A%2F%2Fwww.proquest.com%2Fhistorical-periodicals%2Ffolk-lore-british-plants%2Fdocview%2F6627143%2Fse-2%3Faccountid%3D11620.