Buxaceae
However , its placement and circumscription has varied; some taxonomists treated "Styloceras" in its own family Stylocerataceae , "Didymeles" in its own family Didymelaceae , "Haptanthus" in Haptanthaceae ( now all included in Buxaceae ) ) , and formerly "Simmondsia" was included , which is not related and now usually placed in its own family Simmondsiaceae . 
<triplet> Styloceras <subj> Buxaceae <obj> parent taxon <triplet> Didymeles <subj> Buxaceae <obj> parent taxon