I gathered, I photographed, I consulted, I googled, I read, I Facebooked with foragers, I sniffed, I emailed, I tested, I waited, I nibbled, I waited, I decided. No yellow stain on the flesh when bruised, no weird symptoms in me after my small test piece, I sauteed, I ate. Actually, I had forgotten them until an email from Ellen this evening reminded me that I had mushrooms to eat. Vince was at a party for his work, and so he was spared the ordeal. I think he should write a story called The Forager's Husband.
They were just drop dead (...uh, that was unintentional...) delicious. Agaricus campestris confirmed. Meadow mushrooms. I didn't mess with them. Butter, lemon, salt and pepper, good brown bread, toasted.
I saved one mushroom for a spore print per Ellen's instructions. Up in her Pennsylvanians woods she has yet another crop of black trumpet mushrooms.
And now that I know where these live, I might go back for more.