An investigation of wild plants indicates that there are very few species which are free from possible virus infection. In comparison with this, most flowering plants growing under the surface of open water show a low but significant amount of virus. The indicated level of virus infection varies throughout each summer and from one summer to the next, but is often surprisingly high. The total annual infection under the conditions employed was approximately 10% of sample population. The amount of infection in all plants varies with species and location from 0 to 50%. Total virus infection appears to be related to the growth rates of plants. The types of virus included several common to commercial crop plants, many unidentified mixtures, and some distinctly new viruses.