Along the MKT walking trail through the woods in Columbia, Missouri, there were many patches of these bluebells.  The plant was apparently first documented by early (18th century!) explorers in Virginia, thus the name.  Since this was my first and only sighting, I will probably refer to them as the Missouri bluebells.  Quite lovely!  I understand that they are prolific in the woods and floodplains of Virginia to this day – perhaps I will investigate on a future visit to Virginia!