Not only are the trees of the genus  Taxus posessed of mightily elastic wood – making them excellent materials for bowyery- but their sprigs are symbolic of sadness.  They’re mentioned in the year 985 in the Charter of AEthelred.

06.095 They would shoot at us with their great bows of yew,’
14.018 Now he shot with a great yew bow,

“yew, n.” OED Online. Oxford University Press, March 2015. Web. 19 May 2015.