This species is characterized by its medium-sized to somewhat robust leaves, spiciform inflorescences with up to ca. 1 dozen sessile flowers, small truncate involucels, lobed calyx limbs 4-6.5 mm long, and bright pink to red corollas with tubes 15-20 mm long. The leaves are elliptic-oblong and have closely set well developed intersecondary veins.

Retiniphyllum speciosum is similar to Retiniphyllum rhabdocalyx, which Cortés-Ballén (2003) separated by its calyx limbs 6.3-10 mm long and corolla tubes 20-32 mm long. Both of these are similar in general to Retiniphyllum discolor, Retiniphyllum schomburgkianum and several related species, but those all have smaller elliptic leaves (with rounded margins rather than rather straight side margins). Retiniphyllum discolor and Retiniphyllum glabrum do have similarly-sized red flowers, but Retiniphyllum schomburgkianum and its similar species have white to pink corollas with tubes 10 mm long or shorter.