Rubus c[ae]sius

from The Collaborative International Dictionary of English v.0.48

Dewberry \Dew"ber`ry\, n. (Bot.)
   (a) The fruit of certain species of bramble ({Rubus}); in
       England, the fruit of {Rubus c[ae]sius}, which has a
       glaucous bloom; in America, that of {Rubus canadensis}
       and {Rubus hispidus}, species of low blackberries.
   (b) The plant which bears the fruit.
       [1913 Webster]

             Feed him with apricots and dewberries. --Shak.
       [1913 Webster]