Soapberry tree

from WordNet (r) 3.0 (2006)

soapberry tree
    n 1: a tree of the genus Sapindus whose fruit is rich in saponin
         [syn: {soapberry}, {soapberry tree}]

from The Collaborative International Dictionary of English v.0.48

Soapberry tree \Soap"ber`ry tree`\ (Bot.)
   Any tree of the genus {Sapindus}, esp. {Sapindus saponaria},
   the fleshy part of whose fruit is used instead of soap in
   washing linen; -- also called {soap tree}.
   [1913 Webster]