The Collaborative International Dictionary of English v.0.48:

Brooklime \Brook"lime`\, n. (Bot.)
   A plant (Veronica Beccabunga), with flowers, usually blue,
   in axillary racemes. The American species is Veronica
   Americana. [Formerly written broklempe or broklympe.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

Veronica beccabunga
    n 1: European plant having low-lying stems with blue flowers;
         sparsely naturalized in North America [syn: brooklime,
         European brooklime, Veronica beccabunga]