ABSTRACTColonization of freshly-fallen leaves by buoyant propagules of aero-aquatic fungi was demonstrated by introducingAcer saccharumleaves onto the surface of a small heterotrophic woodland pond. Subsequent degree of colonization byHormiactis ontariensis, Beverwykella pulmonaria, Pseudoaegerita matsushimaeandHelicodendron triglitziensewas significantly correlated with duration of stay on the water surface. The substrate preferences of these fungi were also investigated.Pseudoaegerita matsushimaeandH. ontariensissporulated more frequently on freshly-abscised, than on year-oldA. saccharumandFagus grandifolialeaves.Beverwykella pulmonariaandH. triglitziensesporulated more frequently on year-oldAcer saccharumleaves than on freshly-abscised leaves of the same species.P. matsushimae, H. ontariensisandH. triglitzienseall sporulated more frequently on freshly-abscised than on year-oldF. grandifolialeaves whileB. pulmonariaexhibited no age preference.