The Collaborative International Dictionary of English v.0.48:

Petiolate \Pet"i*o*late\, Petiolated \Pet"i*o*la`ted\, a. (Bot.
   & Zool.)
   Having a stalk or petiole; as, a petioleate leaf; the
   petiolated abdomen of certain Hymenoptera.
   [1913 Webster]