Crat[ae]gus Crus-galli

from The Collaborative International Dictionary of English v.0.48

Cockspur \Cock"spur\, n. (Bot.)
   A variety of {Crat[ae]gus}, or hawthorn ({Crat[ae]gus
   Crus-galli}), having long, straight thorns; -- called also
   {Cockspur thorn}.
   [1913 Webster]