goat's rue

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A North American plant (Tephrosia virginiana) in the pea family, having large yellow flowers marked with purple and grouped in a terminal raceme or panicle.
• noun A Eurasian plant (Galega officinalis) in the pea family, cultivated for its showy, variously colored flowers or as food for livestock.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun perennial subshrub of eastern North America having downy leaves yellowish and rose flowers and; source of rotenone
• noun tall bushy European perennial grown for its pinnate foliage and slender spikes of blue flowers; sometimes used medicinally