The influence of light and nutrition on fruit body development in Asco
bolus biguttulatus was studied. High C and N concentrations inhibited
sexual reproduction. A wide variety of carbon sources supported the pr
oduction of fertile apothecia. Among the nitrogen sources, urea and as
paragine were the best, while inorganic salts resulted in very poor fr
uit body production. Light was an absolute requirement for apothecial
production. When photoinduction was accomplished by single 24-h period
s, the colonies were most receptive at the 5th day of growth. Among ty
pes of light, near ultraviolet light was the most effective.