True prairie was not a matter of location, but of composition. The lie of the land had nothing to do with whether it was prairie or not; if it was tallgrass prairie it included the tallgrass communities. Some prairie was flat, but much of it was rolling, and some was broken and rocky. But it needed tallgrasses if it was to qualify as true prairie—the most easterly of the great American grassland societies that sprawled between the Rockies and the eastern forests.
John Madson, Out Home