The Collaborative International Dictionary of English v.0.48:

Bully tree \Bul"ly tree`\ (b[.u]l"l[y^] tr[=e]`). (Bot.)
   The name of several West Indian trees of the order
   Sapotace[ae], as Dipholis nigra and species of Sapota
   and Mimusops. Most of them yield a substance closely
   resembling gutta-percha.
   [1913 Webster]