Abstract A classification of organic particles based upon their degrada‐tional state and biological origin is outlined for use in palynologi‐cal analysis. The classification has been used in various forms since 1969 and has proved useful in analyzing organic matter from clastic rocks ranging from the Devonian to the Modern. The organic particles are referred to as macerals and are divided into phytoclasts (plant derived), zooclasts (animal derived), protistoclasts (protistan derived), and scleratoclasts (fungal derived). In addition, the term receptorclasts is used to include precipitated organic matter. Phytoclasts are subdivided into the following categories based upon their level of decay: well preserved, no evidence of biodegradation; poorly preserved, minor biodegradation; infested, highly disrupted cell walls; amorphous structured, remnant cell structure only; amorphous non‐structured, blocky mass. In addition to the amorphous non‐structured phytoclasts there are the amorphous non‐structured protist...