Spore print of Agaricus

Spore prints can be very useful as identification aids.  Cut off the stalk and lay the cap on a piece of white paper or a sheet of glass.  Cover with a clear plastic container to prevent rapid drying.   A fresh cap can give a good print in an hour or so (bottom left) or you can leave overnight and get a really heavy deposit of spores (top right).

Note:  The paper was originally white but I changed the background to green to make it stand out a bit better from the background on the webpage!  But you could deduce that if you look at the picture a little more carefully!