I am taking a spore print for any case, if it is white, i will chuck it out, if it is pink then it could be straw mushrooms http://en.wikipedia.org/wiki/Volvariella_volvacea and i will cook them, when immature the mushroom i picked looked like an egg just like a straw mushroom. on mine though a stipe has a ring and volva which could indicate that it is deadly http://en.wikipedia.org/wiki/Amanita_phalloides