This species is characterized by its pilosulous to hirtellous leaves, stems, and inflorescences, medium-sized to somewhat small leaves, spiciform inflorescences with up to ca. 1.5 dozen sessile flowers, small truncate involucels, lobed calyx limbs 2-5.5 mm long, and white corollas with tubes 4-10 mm long and the lobes as long as or longer than the tubes. The leaves are characteristically obtuse at the apices. The corollas range from pale green to cream flushed with pink. Retiniphyllum schomburkii is the most commonly collected species of this genus.

Steyermark (1965) and other authors separated two subspecies and several varieties of this species, based on details of the pubescence, shape of the leaf blade, and average flower size. Cortés-Ballén (2003, and in Taylor et al., 2004) did not recognized any infraspecific taxa, without comment; presumably she found that the characters that supposedly distinguished those taxa are now seen to vary continuously.

Retiniphyllum schomburgkii is similar to several other sessile-flowered species of this genus, in particular Retiniphyllum truncatum, but those all differ in their glabrous leaves, stems, and inflorescences.