Plasmodial Mitoses and Polyploidy in the Myxomycete Physarum polycephalum

Abstract
Propionic orcein squashes of synchronous mitoses in axenic Physarum polycephalum cultures were examined. Chromosome counts indicated 56[plus or minus]2 chromosomes with ca 4% polyploidy. Previous reports were analyzed to explain life cycle stage in which polyploidy originated. An abnormal plasmodial mitosis was suggested as the source of polyploidy. The relationship of polyploidy to conflicting cytological observations in Myxomycete literature was discussed.