The Collaborative International Dictionary of English v.0.48:

Christmasberry \Christmasberry\ n.
   1. a spiny evergreen shrub of southeastern U. S. (Lycium
      carolinianum) having spreading branches with usually blue
      or mauve flowers and red berries.

   Syn: Christmas berry, Lycium carolinianum.
        [WordNet 1.5]

   2. an ornamental evergreen treelike shrub of US Pacific coast
      (Photinia arbutifolia) having large white flowers and
      red berrylike fruits; often placed in genus Photinia.

   Syn: toyon, tollon, Christmas berry, Heteromeles arbutifolia,
        Photinia arbutifolia.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

Lycium carolinianum
    n 1: spiny evergreen shrub of southeastern United States having
         spreading branches usually blue or mauve flowers and red
         berries [syn: Christmasberry, Christmas berry, Lycium
         carolinianum]