I saw this incredibly bright stuff on some maple bark, in a wooded area, after four or five rainy days in July in New Hampshire. I think the producers of “Stranger Things” would be interested. Do you know what it is, and is it toxic? Lawrence
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Hi Lawrence, That’s a slime mold, Fuligo septica, which can be bright yellow. It’s often called scrambled egg slime, or by the even more colorful name of dog vomit slime mold. People typically find it growing on garden mulch. It is not toxic, although some people have an allergic or asthmatic reaction to it.
Biologists are still trying to figure out where slime molds fit into the tree of life. They were once classified as plants. Then as animals. Then as fungi. Now they are thrown into the Kingdom Protista, which is essentially a grab bag of microorganisms that don’t fit into the other Kingdoms: Monera (bacteria), Plantae, Animalia, Fungi. There are several major groups of slime molds, and we’re still not even sure how they relate to each other. Many of the characteristics that seem to make them a group may have evolved separately in multiple groups of amoeba-like organisms.
The bright yellow stage of Fuligo septica is actually one giant cell, with many nuclei. It’s called a plasmodium, and it moves in search of food. When it finds a suitable source of rotting wood, it may settle and then eventually form individual spore bodies, which release microscopic spores. The spores turn into single cells with a single nucleus. If it thrives, it eventually will divide and form many cells, which then form a new plasmodium, and the cycle continues. This site has some nice photos showing what it looks like on the outside:
https://www2.palomar.edu/users/warmstrong/slime1.htm
This site has an illustration of the life cycle of a typical slime mold.
https://www.researchgate.net/figure/Life-cycle-of-a-myxomycete-Illustration-by-Angela-R-Scarborough_fig1_242179415
Tom
I laughed so hard at the dog vomit. I work part time tending to cabins and their grounds and started seeing this yellow mold and at first thought someone had thrown up.