deciduous

Describing a part that falls off, or is shed, at a particular time or stage of development.

In the Hippoidea there is generally the full series of 44 teeth, but the first premolar is often deciduous or wanting in the lower or in both jaws.

Of or pertaining to trees which lose their leaves in winter or the dry season.

. Compare caducous.

a deciduous tree

Transitory, ephemeral, not lasting.