The flowers of Rhinacanthus xerophilus grow in stem-tip cymes. The five, green calyx lobes are linear to lanceolate, the tube shorter than the lobes; the calyx 5 mm long. The two-lipped corolla has a long, thin, hairy tube, cylindrical, straight and pale green, becoming about 2 cm long. The white, three-lobed lower lip and the smaller, narrow upper lip split at the top of the tube. Small dark markings appear near the base of the central lobe. Glandular and other hairs, trichomes, occur on the outside of the corolla. There are two fertile stamens arising in the corolla mouth, bearing exserted anthers. The style is two-branched.

The fruit capsule is oblong and hairy, some of the hairs glandular (Leistner, (Ed.), 2000; JSTOR; iNaturalist).