Adonis vernalis: it's been a strange spring. Note the flower on the left is about spent, while others are still in bud.
There is a species of pachysandra native to the eastern U.S.: Pachysandra procumbens, native from West Virginia down to Louisiana and Florida. Since it isn't evergreen, it will never get the use that the common Japanese pachysandra does. Search on google, and you will be told that the common name is 'Allegheny spurge.'