| Here is a winged seed (10 millimeters in length) from a spruce, collected from the upper Eocene Chicken Creek Formation, Bull Run Basin, Nevada, which appears to most closely resemble a species the late paleobotanist Daniel I. Axelrod called Picea coloradensis, a fossil conifer that cannot be compared directly with any one living taxon, although it shows obvious relationships to two modern species--Picea pungens and Picea engelmannii, the Colorado Blue spruce and the Engelmann Spruce, respectively. |