Physarum cinereum

Physarum cinereum is a species of true slime mold belonging to the genus Physarum, which comprises about 20 percent of the species in the phylum Mycetozoa. This particular species appears as an ashy-gray coating on lawn grasses, typically forming under conditions of high moisture and humidity. While it can be unsightly, Physarum cinereum is harmless and will disappear on its own. The genus Physarum is characterized by violet to brownish spores and a sporangium covered in fine lime granules. Physarum polycephalum is a well-known species within this genus, frequently used in experiments on protoplasmic streaming and nuclear behavior.12