caducous

adj

1. Of a part of an organism, disappearing in the normal course of development.

   “The Jubulaceae have a leaf whose lobule, usually transformed into a water-sac, is normally very narrowly attached to the stem and to the dorsal lobe; indeed some Frullania taxa reproduce vegetatively by dropping the dorsal lobes, but not the lobules, and Neohattoria has caducous lobules but persistent lobes.”

2. Tending to fall early.

   “caducous leaves”