vestigial

1. not comparableOf or pertaining to a vestige or remnant; like a trace from the past.
2. not comparableNot fully developed in mature animals.
3. not comparableevolutionary theoryOf a vestigial structure; that has lost all or most of its original function in the course of evolution.

   Remnants of the vascular supply of lost organs may be present in the tissues of the receptacle when all external evidence of the organs has disappeared. Only rarely does the vascular supply of a vestigial organ disappear while external remnants are still present.

   2004, Pooja, “Flower” (chapter 1), in Pshysiology of the Angiosperms, New Delhi: Discovery Publishing House, →ISBN, Vestigial Vascular Tissue, page 48

plural vestigials

1. evolutionary theoryA small, degenerate, or imperfectly developed part or organ which has been more fully developed in some past generation.