To place a thing into what already stands. First a graft: a living shoot joined into established stock so the two grow as one.
Latin inserere (to join in, graft, plant), from in- (into) + serere (to join, entwine, sow); first a living shoot joined into established stock so the two grow as one.
A graft before it is a mere placement — a living piece joined into an established stock so the two are meant to grow as one.