No, please don't run away screaming. What you have is slime mold. The blanket of mold is actually an aggregation of the individual organisms to form a mass reproductive structure. They disappear as fast as they appear. It is completely harmless. Here is a piece I wrote in my newsletter about them: 

Strange stuff on lawns and bark dust

I had several calls recently about stuff that was alternately called “weird, looking like vomit” or “brightly colored throw up”. The patches were from several inches to about a foot wide and ranged in color from chrome yellow to browns, tans, and cream colors. They were rather amorphous in shape but generally somewhat round, slimy, and knobbly. They grew on grass blades or bark chunks and the thickness varied from a quarter of an inch to more than an inch. The structure could be six or more inches in diameter. If you are of an experimental bent, you could take your hand and move the stuff of the substrate. There you would see the grass or other material completely unaffected.

So what were these things and did they need to be controlled? These organisms are the reproductive structures of slime molds. These “molds” are not fungi, despite their name, but are rather free-living “protists” (basically amoeba) that feed on fungi, bacteria and organic bits.

I first ran into slime molds in some biology classes in the early 1970’s. Science was very interested in how organisms communicated and a great biologist , J.T. Bonner had done ground-breaking work on slime mold communication. His work led ultimately to useful approaches to insect management (pheromone traps) and other scientific discoveries.

These very ancient organisms have evolved a rather complicated reproductive cycle. When they wish to reproduce, often as the food supply dries up, they chemically signal each other (amoeba by amoeba) to aggregate in an area where the wind will carry their spores. So thousands of individuals join together to create this large amorphous structure that was seen in the landscape. They can move as a group and ultimately form group fruiting structures.

These organisms entranced a Japanese scientist in the early 20^th century who collected them and studied them. He hated the slugs that devoured his subjects and woke up every two hours at night to dispatch the slugs. Then he trained cats to do the job.

Slime molds do no harm and disappear usually in a couple of days. For an old but still available interesting article go to http://www.nytimes.com/2011/10/04/science/04slime.html?pagewanted=all

And here is a link to a piece by Kym Pokorny and Neil Bell about them: https://today.oregonstate.edu/news/slime-mold-looks-ugly-garden-does-no-harm

Hope this helps. Chip

Chip Bubl, OSU Extension agent/Columbia County

<personal data hidden>

Linda: Of course you can pass it on, though I am not sure exactly how it is done. It might involve copy and pasting the content. But any process is ok. Chip