The number of Saprolegniaceae found guilty of trespass in other living organisms is not great, and the few culprits that are known to do so are facultative parasites. Nevertheless a broad degree of parasitism is here, from those individuals invading presumably healthy tissue as primary pathogens, to supposedly self-parasitic ones as exemplified by Saprolegnia megasperma (Nolan, 1975a). It is no...