Now, since mushrooms are such fun to know, today every good bookstore and library holds several mushroom books filled with gorgeous color plates. Nonetheless, sometimes it's hard, even impossible, to come up with a mushroom identification in which you have confidence. The problem is compounded by the fact that mushroom spores can travel for hundreds of miles on wind currents, so any truly comprehensive mushroom field guide would have to include species from most of the continent. When I find a new mushroom, my picture-filled field guide called Mushrooms of North America , by Orson Miller, Jr., despite its impressive name, provides an identification in which I have confidence less than half the time. In mushroom identification there's one particularly interesting technique worth giving special mention to.
Spore color is invaluable in mushroom identification.
Unfortunately, usually you can't just sit down next to a mushroom and immediately determine its spore color. Usually you must remove the cap, take it home, and place it on a small sheet of clear glass or paper. Ideally, the paper should have both black and white surface areas so that if the spores are white they'll show up on the black part, if black, on the white. After a few hours, if you're lucky, a beautiful spore print such as that at the left will result. The lines coincide with the gills beneath the cap, from which the spores have fallen.