Viola tripartita var. glaberrima Ging. ex Chapm. split into:

1. V. glaberrima (Ging. ex Chapm.) House
2. V. tenuipes Pollard

Discussion here:
https://www.inaturalist.org/flags/618842

From Harvey Ballard's Website
(formatting added by me for clarity - otherwise verbatim):

Viola glaberrima

• Leaf blades narrowly ovate,
• broadest well above the base,
• base cuneate to broadly rounded;
• margins conspicuously serrate to the tip;
• stem, foliage and peduncles glabrous or sparsely to moderately hirtellous with easily visible hairs;
• north of GA and SC
  

Viola tenuipes

• Leaf blades lance-triangular to rhombic-lanceolate,
• broadest just above the base,
• base broadly cuneate to truncate;
• apical portion beyond broadest point of blade subentire;
• stem, foliage and peduncles minutely puberulent with hairs requiring magnification to see;
• mostly south of TN and NC.