The Collaborative International Dictionary of English v.0.48:

Titi \Ti"ti\, n. [Orig. uncert.]
   1. A tree of the southern United States (Cliftonia
      monophylla) having glossy leaves and racemes of fragrant
      white flowers succeeded by one-seeded drupes; -- called
      also black titi, buckwheat tree, and ironwood.
      [Webster 1913 Suppl.]

   2. Any related tree of the genus Cyrilla, often disting. as
      white titi.
      [Webster 1913 Suppl.]