An unusual pattern of multiple cell and nuclear fusions in the heterothallic slime moldDidymium iridis

Summary Photomicrographic evidence is presented of unusual multiple cell and multiple nuclear fusions in the heterothallic myxomyceteDidymium iridis. These fusions occur only at specific times in the age of the cultured cells and may be induced consistently by the investigator. Once established, the behavior pattern of the multiple-fusion cells is predictable. The possibilities of changes in cell surfaces mediating the multiple fusions are discussed.