I'm not sure about those, but the little brown ones that grow in clumps and have a blueish/purple ring around the stalk are tasty, and go great in the receipe I use for "Inlaw Spaghetti"


KIDDING!

Those do look like Portobello's. I'd suggest going to the grocery store and buying a couple portabello's and doing a side-by-side on smell, appearence, THEN taste..