The Collaborative International Dictionary of English v.0.48:

Pepperidge \Pep"per*idge\, n. [Cf. NL. berberis, E. barberry.]
   (Bot.)
   A North American tree (Nyssa multiflora) with very tough
   wood, handsome oval polished leaves, and very acid berries,
   -- the sour gum, or common tupelo. See Tupelo. [Written
   also piperidge and pipperidge.]
   [1913 Webster]

   Pepperidge bush (Bot.), the barberry.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Tupelo \Tu"pe*lo\, n. [Tupelo, or tupebo, the native American
   Indian name.] (Bot.)
   A North American tree (Nyssa multiflora) of the Dogwood
   family, having brilliant, glossy foliage and acid red
   berries. The wood is crossgrained and very difficult to
   split. Called also black gum, sour gum, and pepperidge.
   [1913 Webster]

   Largo tupelo, or Tupelo gum (Bot.), an American tree
      (Nyssa uniflora) with softer wood than the tupelo.

   Sour tupelo (Bot.), the Ogeechee lime.
      [1913 Webster]

WordNet (r) 3.0 (2006):

pepperidge
    n 1: columnar tree of eastern North America having horizontal
         limbs and small leaves that emerge late in spring and have
         brilliant color in early fall [syn: sour gum, black
         gum, pepperidge, Nyssa sylvatica]