The five versions of the M.G. Nikolaeva seed dormancy terminology and formulae system are correlated to each other and to the dormancy terminology proposed by Baskin and Baskin [Seed Science Research14, 1–16 (2004)]. The proposal is made that the dormancy formula scheme of Nikolaeva [Botanicheskii Zhurnal86, 1–14 (2001)] be adopted as part of an international seed dormancy classification system, and her logic for derivation of the new formulae for physiological and morphophysiological dormancy is discussed via examples. We conclude that there are several advantages of adopting formulae into a seed dormancy classification system. However, Nikolaeva's scheme, especially the part for morphophysiological dormancy, probably needs a small amount of further refinement.
