The Collaborative International Dictionary of English v.0.48:

Wistaria \Wis*ta"ri*a\, n. [NL.] [So named after Caspar Wistar,
   an American anatomist.] (Bot.)
   A genus of climbing leguminous plants bearing long, pendulous
   clusters of pale bluish flowers. Now commonly spelled
   Wisteria.
   [1913 Webster]

   Note: The species commonest in cultivation is the Wistaria
         Sinensis from Eastern Asia. Wistaria fruticosa grows
         wild in the southern parts of the United States.
         [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Wisteria \Wis*te"ri*a\, n.
   Same as Wistaria.
   [PJC]

WordNet (r) 3.0 (2006):

wisteria
    n 1: any flowering vine of the genus Wisteria [syn: wisteria,
         wistaria]