Source : Webster's Revised Unabridged Dictionary (1913)

Indehiscent \In`de*his"cent\, a. [Pref. in- not + dehiscent: cf.
   F. ind['e]hiscent.] (Bot.)
   Remaining closed at maturity, or not opening along regular
   lines, as the acorn, or a cocoanut.

Source : WordNet®

indehiscent
     adj : (of e.g. fruits) not opening spontaneously at maturity to
           release seeds [ant: {dehiscent}]