This species is characterized by its somewhat small leaves, spiciform inflorescences with up to ca. 1 dozen sessile flowers, small denticulate involucels, lobed calyx limbs 8-8.5 mm long, and bright pink to red corollas with tubes 14.5-16 mm long and the lobes shorter than the tubes. The leaves are elliptic to ovate, have closely reticulated but not very prominent veination. Cortés-Ballén (2003) described the flowers as actinomorphic but some recent collections (e.g., Dávila & Acevedo 6073) suggest these may be weakly zygomorphic, with the flowers oriented laterally with style held on the upper side of the flower and the lower lobes more strongly reflexed.

Retiniphyllum discolor is similar to Retiniphyllum glabrum, which Cortés-Ballén (2003) separated by its calyx limbs 5.5-6 mm long and corolla tubes 17-21 mm long. Both of these are similar in general to Retiniphyllum schomburgkianum and several related species, but those all have white to pink corollas with tubes 10 mm long or shorter and the lobes longer than the tubes. These first two species are similar in general to Retiniphyllum maguireorum and Retiniphyllum tepuiense, with pedicellate flowers.