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Dog Vomit Slime Mold

Yesterday while mowing the lawn, I noticed a powdery looking "fungus" type grown on some of the mulch in my back yard. The "fungus" was bright yellow but, at the time, only dusted the ground, as if someone had spilled some of that granular popcorn butter. I looked at it, but didn't think much of it. It's right near where Carey throws out some old food occasionally (for the birds), so I thought perhaps a bright little fungus had sprung up. Having seen far too many episodes of House, however, I did call Carey to tell her that if I became deathly ill in the next few days, it was likely due to this bright yellow fungus in the back yard. 😛

Six hours later it was dark, but I decided to check out the fungus. HOLY COW! The thing was suddenly puffy and about twice the size that it was before!

Slime Mold 01Slime Mold 02

I did some research. I had to - at this rate of growth, the thing would cover half my back yard by the time I woke up.

It turns out I needn't have bothered, really, except to satisfy my curiosity. Various gardening websites answered my query of "bright yellow fungus on mulch" by telling me that bright yellow fungus on mulch wasn't a fungus at all, but rather a kind of slime mold commonly referred to as "Dog Vomit." ((Presumably because it looks a bit like dog vomit - which is fairly accurate.))

A "slime mold" is term used to refer to about six kinds of eukaryote. A eukaryote, for those who don't remember back to high school biology, is an organism which contains a membrane-bound nucleus. What makes slime molds interesting is that these nuclei aren't contained one per cell, as the slime mold lacks true cell membranes. Rather, thousands or millions of nuclei float about in an cytoplasm that's been clocked as moving as fast as 1.35mm per second. Most slime molds are small, but they can grow to as large as 30 square meters, making them the largest undivided cells in the world.

I monitored the growth of the slime mold throughout the evening until I went to bed at about 1am. It was growing rapidly, so I put some tees in the ground around the perimeter so that I could at least visually measure how quickly it was growing.

Having learned that the "Dog Vomit" (or, more properly, Fuligo septica) was harmless, I stuck my finger in it and swished it around. The best I can describe is "a very puffy, low density glue." Unfortunately, "Dog Vomit" doesn't last very long. By the time I woke up the next morning, it was starting to die off.

Slime Mold 03

Slime Mold 04

The end is even less pretty. It'll turn brownish black and powdery, and release thousands of spores. A great majority of them won't find anywhere to spring up. A few might and will spawn yet another of these fascinating little creatures.

That brown spot in the images above is where I felt up the slime mold with my fingers. Exposed to the air, I guess, that portion of the slime mold quickly "died."

You can read more on slime molds here, here, here, and here.

6 Responses to "Dog Vomit Slime Mold"

  1. Charming name.

  2. ... gross.

  3. OMG! That's disgusting! 😆

  4. I had the exact same stuff on my deck. It was gross.

  5. Thanks so much! I thought that I may get sick, too. I just messed with the strange growths to release amazing brown powder bombs. As a beginning gardener, my confidence was flailing...

  6. Am I a bad person? Before I did an Internet search, I decided that this invader should be nipped in the bud. I mixed a 25% bleach, 75% water solution in my spayer and sent it back to its maker. Oh, the shame!