Most of them do well in the south. Do a google search with the terms "amelanchier louisiana" or "amelanchier mississippi". You will get plenty of information.

According to the NatureServe database (a wonderful resource, link below), there are 2 apecies that are native to Louisiana, arborea, and canadensis.

Shelley

Here is a link that might be useful: NatureServe Explorer

I've seen A.alabamensis in the D.E. Davis Arboretum on the Auburn University campus, but don't know what features differentiate it from A.arborea.
A.obovata is a southern-origin serviceberry; the "Jennybelle" selection has been available from a small number of sources in the past. It's a loose, sprawling large shrub/small tree, and at least in my plantings here in southern KY, is less desirable than A.laevis(Allegheny serviceberry), and fruit quality is much poorer than A.laevis, A.xgrandiflora, or any of the A.alnifolia selections.