This tree is on the north side of Magnolia Lawn, across from the University School front entrance.

Ashes can be recognized by their pinnately compound, opposite leaves.  Green ash is a dioecious species, and this particular tree is a female.  In the fall it provides an opportunity to observe the paddle-shaped fruits.  Distinguishing between green ash and white ash (Fraxinus americana) can be difficult but the wings on the green ash fruits tend to extend along the edge of the fruit towards its base, while the wings of the white ash fruits tend to stop at the thick part of the fruit.  Large trees of both white and green ash tend to have bark that is broken up into square-ish plates.  Another ash species that is common in middle Tennessee (but not represented in the arboretum) is blue ash (Fraxinus quadrangulata).  It is easily distinguished from white and green ash by its square twigs which are quite different from the round green ash twigs and white ash twigs.