There are several species of Polygonatum in Indiana. It seems that each different field guide you look at shows a different set. The Plants Database shows two species, this one and Polygonatum pubescens (Hairy Solomon’s Seal). It seems that this genus has been split and lumped several times.
Basically, the Smooth Solomon’s Seal has smooth leaves and the Hairy Solomon’s Seal has, you guessed it, hairy leaves.