This app was mentioned in 1 comment, with an average of 3.00 upvotes
It depends of where you are based but i live in Québec and i use this app: La fonge du Québec
It's only in french at this time but i guess they will translate it once they get more than 2 volunteers to do it.
Its specializing in mushrooms that were found in the province of Québec based on the Mycoquebec website.
From the app page it says: "At this time, the app contain about 2491 species illustrated with 17949 photos and about 2422 that are described at the macro and microscopical level.
All in all its a decent app but it's not really optimized unfortunatly.
[Edit] Just saw your flair, this app won't be for you then since it's more about north east american mushrooms. I'll keep my comment up in case it helps someone else