Geographic distribution of sampled populations of L. alabamica and L. crassa within northwestern Alabama. L. alabamica populations (circles) are numbered 1–10: Isbell, Tuscumbia, Speck, Hatton, Winchell, Russell, Landers, StCross, CPCC and CR46, respectively. L. crassa populations (triangles) are numbered 11–15: CR203, CR55, Quarry, Bramlett and NCP, respectively. The inset (lower right) shows the location of the map area (shaded) within Alabama. L. alabamica's range extends from population 2 to 9, and L. crassa's from population 11 to 13.