ID this fungus please

Asked July 8, 2020, 11:59 PM EDT

What is this? (See attached image.) Appx 1 foot in diameter, orange, "rolls" like a wave, white "tendrils" near outside. It doubled in size (circumference) in a single day. Growing on hemlock bark. Never seen it before, here or anywhere else.

Linn County Oregon

1 Response

Thank you for the images.

That strange looking mass is called slime mold. It's fairly common but always surprises people who see it for the first time. It's not a fungus, but is an aggregation of very small organisms that move as if a single animal.

Slime molds move over mulch and.or soil as they feed on microorganisms that live in any type of dead plant material. Sometimes they'll climb a plant stem but won't damage it. Slime molds thrive in moist places/seasons.

You need not get rid of it because it will stop moving, dry up, and will disintegrate. But if you must, scoop it up and put in your compost pile or the trash.

"Discovering Slime Molds" has some background information and includes a brief time lapse video of the changes it undergoes over 24 hours. (https://botanicgardens.uw.edu/about/blog/2017/06/07/june-plant-profile-discovering-slime-molds/)