Herbertia it is a genus in Iridaceae family. It comprises 8 species. One native to USA, others native to South America.
http://en.wikipedia.org/wiki/H...
The species native in USA is
Herbertia lahue (Molina) Goldblatt, common name Prairienymph or Prairie Nymph.
Wikipedia says that is endemic in texas but USDA says that distribution is Florida, Louisiana, Mississippi and Texas.
http://plants.usda.gov/java/pr...
Looking at the map on the page above, I think it's possible to find the plant in the coastal zone of Alabama, too.
Useful link
http://www.wildflower.org/plan...
As the common name, Prairie nymph, suggest, it is an exotic beauty. Small and delicate.
April 08, 2013, Victoria, Tx.