Crowberry

from WordNet (r) 3.0 (2006)

crowberry
    n 1: a low evergreen shrub with small purple flowers and black
         berrylike fruit

from The Collaborative International Dictionary of English v.0.48

Crowberry \Crow`ber`ry\ (kr?"b?r`r?), n. (Bot.)
   A heathlike plant of the genus {Empetrum}, and its fruit, a
   black, scarcely edible berry; -- also called {crakeberry}.
   [1913 Webster]