Source : Webster's Revised Unabridged Dictionary (1913)

Stipule \Stip"ule\, n. [L. stipula a stalk, stem, straw: cf. F.
   stipule. Cf. {Stubble}.] (Bot.)
   An appendage at the base of petioles or leaves, usually
   somewhat resembling a small leaf in texture and appearance.

Source : WordNet®

stipule
     n : a small leafy outgrowth at the base of a leaf or its stalk;
         usually occurring in pairs and soon shed