CHAPTER III. Nomenclature of taxa according to their rank
SECTION 5. Names of taxa below the rank of species (infraspecific taxa)
For nomenclatural purposes, a species or any taxon below the rank of species is regarded as the sum of its subordinate taxa, if any.
When Montia parvifolia (DC.) Greene is treated as comprising two subspecies, the name M. parvifolia applies to the species in its entirety, i.e. including both M. parvifolia subsp. parvifolia and M. parvifolia subsp. flagellaris (Bong.) Ferris, and its use for M. parvifolia subsp. parvifolia alone may lead to confusion.