The team had earlier figured out that the basic starting material for bioluminescence in these fungi is a compound called hispidin, found in some other fungi as well as plants such as horsetails. Those plants don’t spontaneously give off light, but in the two Neonothopanus mushroom species, an enzyme rejiggers a form of hispidin into a compound that glows. The enzyme that turns a fungus into a natural night-light isn’t that fussy as enzymes go, says Cassius V. Stevani of the University of São Paulo in Brazil.