Source : Webster's Revised Unabridged Dictionary (1913)

Bean trefoil \Bean" tre"foil\ (Bot.)
   A leguminous shrub of southern Europe, with trifoliate leaves
   ({Anagyris f[oe]tida}).

Source : WordNet®

bean trefoil
     n : shrub with trifoliate leaves and yellow flowers followed by
         backward curving seed pods; leaves foetid when crushed
         [syn: {stinking bean trefoil}, {Anagyris foetida}]