It is a perennial herb or subshrub, 5-10 cm tall, with cylindrical stems covered in short soft hairs and circular leaf scars and pores. Its leaves are alternate, thick and papery, elliptic to obovate or spoon-shaped, 1-1.5 cm long and 5-8 mm wide, with blunt tips and short pointed bases. The upper surface is slightly concave with raised veins, while the lower surface is rough and hairless, with 2-3 visible veins. Leaf margins are entire, green with dense white short stiff hairs near the edge.
It is found in Guizhou and Yunnan provinces of China, growing on mountain slopes under Pinus forests or on open mountainsides, at around 1900 meters above sea level.
Details about the fruit are not specified in the text.
Polygala dunniana differs from P. saxicola and P. koi in having smaller, elliptic to obovate or spoon-shaped leaves (10-15 mm long, 5-8 mm wide) covered with white transparent short stiff hairs near the leaf margin. Its inflorescence is very short with few large flowers (18 mm long), white or pale green-white in color, with the keel petal having 4 finger-like appendages.