The Collaborative International Dictionary of English v.0.48:

Catalpa \Ca*tal"pa\, n. [From the language of the Indians of
   Carolina, where Catesby discovered this tree in the year
   1726.] (Bot.)
   A genus of American and East Indian trees, of which the best
   known species are the Catalpa bignonioides, a large,
   ornamental North American tree, with spotted white flowers
   and long cylindrical pods, and the Catalpa speciosa, of the
   Mississipi valley; -- called also Indian bean.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Catalpa speciosa
    n 1: catalpa tree of central United States