R. David Whetstone in Flora of North America (vol. 2)
Leaf blades broader than long. Pollen cones lax, elongate. Ovules often abscising before fertilization. Seeds 1--2 per peduncle. The genus is known from fossils that date back nearly 200 million years and are nearly identical to present-day trees.
Species within checklist:
Utah State University - Logan Campus