from
The Collaborative International Dictionary of English v.0.48
buckbean \buckbean\, Buck bean \Buck" bean`\(b[=e]n`). (Bot.)
A perennial plant ({Menyanthes trifoliata}) of Europe and
America which grows in moist and boggy places, having racemes
of white, reddish, or purplish flowers and intensely bitter
trifoliate leaves, sometimes used in medicine; marsh trefoil;
-- called also {bog bean}. It often roots at the water margin
and spreads across the surface.
Syn: water shamrock, bogbean, bog myrtle, marsh trefoil,
{Menyanthes trifoliata}.
[1913 Webster + WordNet 1.5]