The Collaborative International Dictionary of English v.0.48:

Casuarina \Cas`u*a*ri"na\, n. [NL., supposed to be named from
   the resemblance of the twigs to the feathers of the
   cassowary, of the genus Casuarius.] (Bot.)
   A genus of leafless trees or shrubs, with drooping branchlets
   of a rushlike appearance, mostly natives of Australia. Some
   of them are large, producing hard and heavy timber of
   excellent quality, called beefwood from its color.
   [1913 Webster]

WordNet (r) 3.0 (2006):

casuarina
    n 1: any of various trees and shrubs of the genus Casuarina
         having jointed stems and whorls of scalelike leaves; some
         yield heavy hardwood