Yesterday I introduced the plasmodium phase of scrambled egg slime mold. The second growth stage of scrambled egg slime mold (Fuligo septica) and other slime molds is called an aethalium and is comparable to the spore-bearing fruit of the mushroom. I previously posted another slime mold, Wolf’s milk slime.
The trigger for the change from plasmodium to aethalium is not known, perhaps the slime mold run out of food, is satiated, or maybe light or moisture initiate the transition. Although the spores of some slime molds form in little blobs or balls, with or without stems on the surface of the organism, the aethalium of scrambled egg slime mold is cushion shaped, slimy and filled with spores when young. As it matures, the outside of the cushion gets crusty while the dark brown or black spores appear cakelike when the aethalium is cut. Eventually the aethalium degrades and releases the dark spores.
This transition can happen quite rapidly. When I first saw the cushion in the picture it was a slimy yellow and soft. I touched the surface and exposed the dark spores inside before continuing my hike along the North Umpqua Trail (Oregon). Perhaps two hours later I re-examined the aethalium on my return and was surprised to find that it was already crusty. One picture shows where I touched the aethalium while it was slimy. The crusty surface (called a peridium) and cakelike spores in the cut aethalium are visible in another photograph taken about two hours later. Finally, the bottom surface in contact with the decaying wood substrate is shown. Obviously the mature aethalium is not shapeless protoplasm.
Scrambled egg slime mold is not edible.
This common slime mold is a subject of scientific interest because extracts of scrambled egg slime mold show antibiotic activity against the bacteria Bacillus subtilis and antifungal activity against Candida albicans.
Additionally scrambled egg slime has a unique resistance to zinc and accumulates extremely high quantities of this metal, amounts that should be toxic to the slime. Research has shown that scrambled egg slime mold contains a yellow pigment, fuligrubin A, that chelates zinc and turns it into an inactive form, allowing it to survive what should be a lethal amount of zinc.
What a fascinating organism!