When Arboretum employee and artist Nancy Hart designed The Morton Arboretum logo in 1972, she was inspired by the white oak images on J. Sterling Morton's book plates. The white oak (Quercus alba) is also the state tree of Illinois.
The logo is symbolic: The leaves to the left of the base of the tree represent the years that have passed. The full-grown tree signifies the present. The acorns to the right of the tree anticipate the future.