From Roland Fox, School of Plant Sciences, University of Reading
Has anyone investigated whether these “fairy circles” on the western fringes of the Namib desert are the same as the fairy rings caused by fungi that appear on lawns in the UK during the spring and summer (3 April, p 12)?
The feature that seems most similar to the Namibian phenomenon is that the first visible evidence of a new fairy ring is a circle of stimulated grass that develops on the nitrogen released after the fungus breaks down organic matter in the soil. Fairy rings are caused by several soil-inhabiting fungi that feed on organic matter in the soil. These dark green or brown circular rings, a few centimetres to 15 metres in diameter, are caused when a fungus grows outward from a central point. If it meets another ring it stops growing, resulting in a scalloped ring.
A ring of brown or dead grass may also develop due to a dense growth of white mycelium that does not allow water to penetrate. Mushrooms can develop in a circle outside the dark green or brown ring after autumn rain – assuming, of course, that the little folk danced sufficiently well the night before.
Reading, Berkshire, UK
