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 americana
    n 1: plant of western North America and northeastern Asia having
         prostrate stems with dense racemes of pale violet to lilac
         flowers [syn: brooklime, American brooklime, Veronica
         americana]