The fine line between Delicious and Death

I went mushroom hunting on sunday with Jane, Brad, and their hungarian host mom. We spent 3 hours walking in the forest of the Voges mountains, which was beautiful in itself, while we learned the ins and outs of french mushrooms.
Like a well worn fairy tale we filled up our bags and baskets with all shapes and sizes of fungus, drove home in the sunny afternoon, cleaned the mushrooms while listening to gypsie music on the radio, and then Madame made the most delicious mushroom tarte I have ever had in my life. The mushrooms were fresh and tasted different than the type you can buy at the store.
When I went to the store today to buy cheese I saw the very same mushrooms for sale, for 16 euro per kilo.