Stemonitis

Janna Beckerman, Department of Botany and Plant Pathology, Purdue University

This is the immature spore bearing structure called sporangia, of Stemonitis (Figure 1). Also called the ‘chocolate tube slime mold’, when mature, this organism looks like brown hairs growing on wood or leaf litter (Figure 2). Slime molds are not fungi, but are Myxogastria, and actually more closely related to animals, so put away thoughts of any fungicide! Stemonitis is a plasmodial slime mode, meaning that blob you are seeing is technically called a plasmodia. By the way, it’s naked! This actually means they don’t have cell walls! The plasmodial masses of protoplasm can move and engulf available food, like an amoeba, or ‘The Blob’ if you are old enough to remember the movie. Slime mold plasmodia ‘creep’ over the surfaces of materials, engulfing and eating whatever it can (don’t panic—we’re talking bacteria and other protozoans). At some point, the plasmodia convert into spore-bearing structures shown in the photo. The spores are released, and it starts all over.

Figure 1

Figure 2