RESUMEN
The application of the group theory to description of biological objects pseudosymmetry is introduced and substantiated by the example of rotatory symmetry of actinomorphic and zygomorphic flowers. Problems of biosymmetrics terminology are considered; point symmetry elements are characterized as being applied to description of flower symmetry; central constructs of the group theory are stated. Application of the Curie principle to biological objects is outlined. Algorithms for quantitative assessment of flower pseudosymmetry are given; the description is made of flower pseudosymmetry in the terms of the group theory, including evolutionary aspect. The conclusion is made that adaptation of the group theory to description of biological objects symmetry (biosymmetrics) is important not only in fundamental respect but also as a tool of inter-disciplinary mutual understanding between biologists, physicists, crystallographers and other specialists whose communicative language is mathematics.