Infraspecific categories in flowering plants

Infraspecific categories imply infraspecific classification, but there are few species whose internal diversity has been sufficiently studied to permit this in any detail. Important variation may be physiological, continuous and unassociated with convenient morphological markers. Conspicuous variation may be biologically trivial and the use of names for these variants gives a misleading view of the species-structure. If we are to classify we must know the relation between the internal and external characters. The suitability of a hierarchical system cannot be assumed. Informal classifications are likely to be of more use than those provided by the Code of Nomenclature. Nevertheless variation undesignated may easily become variation overlooked.