Compared to P. biserrata (P. serratifolia) in the original description (that species was found growing near to this one but at a higher altitude) with similar flowers though not bicolored and with smaller, thicker leaves with a distinct toothed margin. P. melanodonta is efarinose, scape to 25cm with usually one, but sometimes two superposed whorls of yellow flowers. The calyx is ribbed, stained red, cut to the middle into acute teeth. Usually flowers in Spring, but some plants may flower in Fall. Found growing in the area around the junction of Myanmar, Xizang and Arunachal Pradesh. Compare with P. prenantha, P. morsheadiana and P. brachystoma.