Abstract
Spore walls of Lycopodium clavatum, after oxidation using ozone for varying times and treatment with dilute alkali, showed a striking loss of the outer layer (muri) of the exine. Almost all trace of the muri and undetermined portions of the remaining exine wall were removed after 20 hours' oxidation. The exine wall material seems to be evenly removed. The only degradation patterns observed are rare pits after 20 hours oxidation. A degradation-related colour change of the spore wall occurs after 11 to 16 hours' oxidation.