Help identifying brown blobs growing in my garden

Asked December 5, 2018, 5:47 PM EST

I noticed cracks in the surface of a berm that has about 4 inches of mulch covering it. At first I thought it might be a bulb pushing up or some vermin digging underground, but instead I found this (see attached image). Do you have any idea what it is? The blob is fairly light weight, about 2 inches across and resembles an ordinary dirt covered rock but it is a little bit spongy in texture--not hard like a rock. The berm where I found it has a medium sized lace leaf maple growing on it, and a variety of small Oregon native plants around it. However, the entire berm is directly under a very large (70+ year old) Douglas Fir tree. The "blobs did not appear to be attached to a tree root (otherwise I might think these were truffles--wouldn't that be nice!) but I rather doubt that is the case. I am mystified as is my neighbor who is a master gardener. What do you think it might be?

Multnomah County Oregon forestry urban forestry

2 Responses

This looks like Pisolithus arhizus, a common fungus which is symbiotic and beneficial to trees and shrubs.

That's good to know! Thank you so much. --Jan