What kind?
“What kind?”
Exactly LOL. You mean the shrooms’ you find at at the grocery or the shrooms’ they handed to me back in college?
The researchers found that white button mushrooms, the most commonly consumed kind in the U.S., have about 12 times more of the antioxidant than wheat germ and 4 times more than chicken liver, the previous top-rated ergothioneine sources based on available data. Until the Penn State researchers developed their testing approach, known asan assay, there was no method employing the most sensitive modern instrumentation and analytical techniques to quantify the amount of ergothioneine in fungi. The researchers say that their assay can be used for other plants, too, not just mushrooms.
https://www.sciencedaily.com/releases/2005/09/050912080429.htm