Lycopodium is a yellow-tan dust like powder historically used as a flash powder. It is composed of the dry spores of clubmoss plants. When mixed with air, the spores are highly flammable because of their high fat content and their large surface area per unit of volume - a single spore's diameter is about 33 micrometers. Preferred sources are Lycopodium clavatum (wolf's-foot clubmoss) and Diphasiastrum digitatum (common ground cedar)

Lycopodium has been used in fireworks and explosives, fingerprint powders, as well as a covering for pills, and as a ice cream stabilizer. Today, the principal use of the powder is to create flashes or flames that are large and impressive but relatively easy to manage safely in magic acts, for cinema and theatrical special effects. The powder is also highly hydrophobic; if the surface of a cup of water is coated with lycopodium powder, you can put your finger into the cup and it will come out dusted with the powder but remain perfectly dry.