La·bur·num n. Bot. A small leguminous tree (Cytisus Laburnum), native of the Alps. The plant is reputed to be poisonous, esp. the bark and seeds. It has handsome racemes of yellow blossoms.
Note: ☞ Scotch laburnum (Cytisus alpinus) is similar, but has smooth leaves; purple laburnum is Cytisus purpureus.
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