Collection location: Corte Madera, Marin Co., California, USA [Click for map]
I think this is a Leptonia because of the pink gills and metallic green stipe and cap. It didn’t drop enough spores to be able to see a spore print color, and I am not sure about the genus.
Could this be Leptonia violaceonigra? It looks similar and was growing in similar habitat, but I can’t find the species description.
Where is a good source of info for these kind of things? It didn’t key our well using Mushrooms Demystified.
I agree that it’s a Leptonia. The best reference for them is Largent’s Entolomatoid Fungi of the Western United States and Alaska, but it is a daunting book that relies heavily on microscopic characteristics. Unless you have the dried specimen and a few more specimens, I’d just go with Leptonia sp. and maybe expand on the notes to include habitat and anything thing else notable about this collection. I’d particular include features you used when working with Arora’s key.