Native Missouri Tree Collection Bartram's Oak (Quercus x heterophylla), a natural hybrid frames the Life Sciences Center. This young collection of native Missouri trees is located at the corner of College Avenue and Rollins Street near the Life Sciences Center. Trees such as Sour Gum (Nyssa sylvatica), found in the Ozarks, White Fringe Tree (Chionanthus virginicus), native to the extreme southern part of the state, Sassafras (Sassafras albidum), which grows statewide, Pawpaw (Asimina triloba), a hardy tropical-looking small tree and Hackberry (Celtis occidentalis) are growing in this garden. Donor: Allan and Vivian Purdy Paw Paw (Asimina triloba) is the only species of a tropical family of custard apples (Annonaceae) hardy enough to grow in Missouri. The fall fruit is a delicate custardy treat. White Fringe Tree ( Chionanthus virginicus) in full flower.