Not a Killer App, but one that can KILL YOU.
Doctor Cortinarius write:
The good news is that the app creators offer a note which warns us that incorrect mushroom identification can be fatal. They're right about that. And some of the other information here isn't too bad. They provide Latin species names and link to additional info on the Web (though Wikipedia as a source is questionable).
BUT... One very serious error in judgment, in my opinion, is to show any species of Amanita and list its ediblity as GOOD (A. vaginata) or VERY GOOD (A. caesarea). Amanita species include THE most deadly mushrooms known and identification can be very tricky. People die regularly from mistaken identification--even experienced pickers. And it's an excruciatingly painful, drawn-out death with multiple organ failures. Listing any Amanita as edible without an explicit and very visible warning attached is highly irresponsible.
Also, I don't like the prominent, simplistic labeling that puts edibility at the forefront of identification--GOOD/VERY GOOD/BAD/POISONOUS... This kind of thinking can rush one's judgement. Even correctly identified edible fungus species can cause a toxic reaction in persons with unknown sensitivities.
You need more than an iPhone to learn about mushroom identification. I think the creators of these types of applications should be more focused on offering tools to help people learn about proper identification of fungi, and leave edibility as a secondary concern.
Encouraging anyone to eat a mushroom that has not been identified with 100% certainty is unethical.