glauca 4a sugar maple Acer saccharum 4b yellow-wood Cladrastis lutea 4b Scotch elm Ulmus glabra 5 Norway maple Acer platanoides 5 English oak Quercus robur 5a Douglas maple Acer glabrum var.
One paleobotanist's Cladrastis or Magnolia has become another's Nyssa (Wolfe, 1966; Tanai, 1977); the same is true of Bombax, Quercus, Juglans, Persea, and Laurus (Hantke, 1965; Knobloch, 1969; Kvacek & Buzek, 1972; Kvacek & Walther, 1972, 1981; Mai & Gregor, 1982).
Four examples suggest the range of trees spotlighted: Acer griseum, the paperbark maple; Cladrastis lutea, yellow wood; Magnolia acuminata, cucumber tree; and Parrotia persica.