On our travels this spring, I purchased these cards at Stephen F. Austin State Park in Texas. The art is called quilling.
I took this from the web to explain what quilling is:
Quilling is the art of rolled, shaped, and glued paper that results in creating a unified, decorative design. The name quilling is thought to come from the origin of the art; birds’ feathers, or quills, were used to coil the strips of paper around.