For a plant physiologist who is not initiated in the field, the term "peroxidases" still represents a true morass. The points which cast a certain doubt as to peroxidases really playing a causal role in developmental physiological processes are reviewed. These points are being argued taking into consideration some recent developments in the knowledge of the properties of these particular enzymes. A place and a role for some peroxidases in a general sequence of reactions which, at different degrees, would be operating in the physiology of plant growth and development, are proposed.