subspecific

Adjective

 * 1)  pertaining to a subspecies. (See Usage notes.)
 * 2)  infraspecific. (See Usage notes.)

Usage notes
Formal usage (that is, as a term of formal nomenclature referring to the taxonomic rank of subspecies) is only in zoology and bacteriology, not in botany, although informal usage is not restricted. When the meaning of is meant (that is, pertaining to any taxon at a rank lower than species), it is preferable to say  (because the main  of  refers more particularly to subspecies per se), although the broad usage is venial.