CADUCOUS
caducous, shed
(adjective) shed at an early stage of development; “most amphibians have caducous gills”; “the caducous calyx of a poppy”
Source: WordNet® 3.1
Etymology
Adjective
caducous (comparative more caducous, superlative most caducous)
(biology) Of a part of an organism, disappearing in the normal course of development.
(botany) Tending to fall early.
Source: Wiktionary
Ca*du"cous, Etym: [L. caducus falling, inclined to fall, fr. cadere
to fall. See Cadence.] (Bot. & Zoöl.)
Definition: Dropping off or disappearing early, as the calyx of a poppy, or
the gills of a tadpole.
Source: Webster’s Unabridged Dictionary 1913 Edition