If you plan to forage for wild mushrooms—and even if you’re growing your own mushrooms outdoors—making spore prints is an important skill to master. Fortunately, you don’t need much equipment to make mushroom spore prints. And they can afford valuable clues to help you get closer to identifying different mushroom species.
While plants produce seeds, mushrooms—the fruiting bodies of a fungal mycelium—produce spores. A single mushroom can release hundreds of thousands of spores.
As with plant seeds, mushroom spores differ in color, shape and size. You need a microscope to really study their shape and size. But you easily can determine their color by making spore prints.
Discerning a particular mushroom’s spore color can help narrow down an identification. This is particularly helpful for ruling out lookalike species.
How to Make Mushroom Spore Prints
To make mushroom spore prints, you need scissors, a small cup or bowl, and heavy paper or card stock in both light and dark colors. That’s because spore colors range widely. (For instance, if you want to confirm that you have a specific type of oyster mushroom like the ones I found in this video, you’d want to use dark-colored paper, because oyster mushroom spores are often white to pale lilac.)
So, whitish spores show up best on dark backgrounds. And spores in dark browns and black are easiest to see on light backgrounds. (Alternatively, you can make temporary spore prints on a pane of clear glass and then place the glass on either a light- or dark-colored background as needed.)
To start, cut the mushroom’s stem away from the cap, so that the cap will lie flat against your paper. Place the cap with its spore-releasing gills facing down. Next, cover the mushroom cap with the cup. Don’t jostle or disturb the print-in-progress for the next several hours.
When it’s time to peek at your mushroom spore prints, remove the cup and gently lift the mushroom cap from the surface of the paper. You should be left with a clear outline of the mushroom’s gills and other internal structures—made up of its own colorful spores.