This Post does a high quality position of detailing what to be careful of when distinguishing concerning psilocybe semilanceata and its doppelgangers. Once the veil disintegrates it leaves a location around the stem, where it had been attached, that darkens with age. This spot is known as the “annular zone.” https://psilocybinuk.co.uk/product/fresh-black-autumn-truffles/feed/