Poisonous plants. Historical artwork of two types of poisonous plant. The laburnum (Cytisus laburnum) produces yellow flowers (upper left) from which seed pods develop. Laburnum leaves are used in herbal medicine for a purgative effect and contain the poisonous chemical cytisine. Yellow vetchling (Lathyrus aphaca) leaves and flowers (right) are seen on a vine. This plant is a member of the pea family. A pod of seeds is shown at lower centre. This plant is also poisonous. From The Instructive Picture Book or Lessons from the Vegetable World, Charlotte Mary Yonge, 1857.