Inflectional classes are a property of the ideal inflecting-fusional language type. Thus strongly inflecting languages have the most complex vertical and horizontal stratification of hierarchical tree structures. Weakly inflecting languages which also approach the ideal isolating type or languages which also approach the agglutinating type have much shallower structures. Such properties follow from principles of Natural Morphology and from the distinction of the descendent hierarchy of macroclasses, classes, subclasses, subsubclasses etc. and homogeneous microclasses. The main languages of illustration are Latin, Lithuanian, Russian, German, French, Finnish, Hungarian and Turkish.