IMPLICATIONS OF THE EQUIVALENCE OF SUBSPECIES AND VARIETY, AND OF THE IRRELEVANCE OF FORMA

At least four problems beset infraspecific classification of wild and cultivated plants. 1) There is taxonomic confusion and ambiguity with regard to classifying wild versus cultivated plants. 2) Some taxonomists recognize botanical taxa, usually as formae, that are sets of individuals rather than of natural populations. 3) Subspecies and varieties are theoretically and practically indistinguishable, but both are currently used; and the choice relates more often to the geographic origin of the taxonomist than to the biology of the plants. 4) Although some flora editors prohibit the practice, some taxonomists erect multiple-rank infraspecific classifications. These problems may be addressed through changes to the botanical Code and/or to taxonomic practice. 1) Botanical and cultivated plant classification should be clearly distinguished from one another, with botanical ranks-subspecies, variety, forma-defined solely as sets of natural populations. 2) The use of forma should be abandoned, because it usually is defined as a biologically arbitrary set of individuals, not of populations. 3) Either subspecies or variety should be designated in the Code as the sole, or at least the primary, infraspecific rank; or else botanists should change to trinomial nomenclature, consistent with zoologists, in which the third epithet is no longer labelled.