Making a Spore Print

Identification of wild mushrooms is tricky business. As mushrooms grow and mature they change in size, shape and often color. While some change color from brown to buff or dark yellow to light yellow, some turn from blue to brown or red to buff, changing completely and making accurate identification tricky.

So you are thumbing through the field guide and have narrowed the search to two or three mushrooms, but can’t really decide for sure which one it is. The only thing left is a spore print. According to the book, one mushroom has a white spore print, while the other has a green spore print. Sounds easy enough, right, but what is a spore print? A spore print is a mass of spores deposited on a surface, usually a piece of paper. Having millions to billions of spores in one place allows you to determine overall characteristics of the usually microscopic spores, such as color. As a bonus, making them is easy and fun to do with the kids.

First of all, select a mushroom, preferrably one that is mature enough to be producing spores. In other words, if you can’t see the gills yet, you won’t get any spores. If it is a polypore mushroom (little holes on the bottom instead of gills all lined up), the pores should be open. Lay the mushroom with the gills or pores down on a piece of glass or a piece of paper. If the field guide says the spore print is white, you won’t be able to see it on white paper, so pick a different color of paper. Then just cover it with a bowl to keep air flow out. Any moving air in the room will carry the spores off. Then just let it sit for somewhere between 2 and 24 hours. The longer you let it sit, the more spores you will get, and the darker it will be. You can pick it up and check it periodically if you want, but that will ruin the cool pattern you will get from the gills of the mushroom. That’s it. you have made a spore print.

If it turns out to be a mushroom you want to keep around, you can let the spore print fully dry and then fold it up and keep it. The spores will remain viable for 3 years or so.

Some mushroom hunters will make spore prints of choice edibles on tops and brims of their favorite hiking hats. That way the spores will be spread from their hat by the breeze as they hike, helping spread the tasty mushrooms.