Clermontia pyrularia is a species of shrubs or trees that can grow 2 to 6 meters tall and thrive in terrestrial and epiphytic environments. It has light gray or brown stems branched repeatedly and spread out, with a solid pith and white, viscous latex. The leaves are simple and alternate, with elliptic or oblanceolate blades 7–16 cm long and 1.5–4 cm wide, featuring dark green, glossy upper surfaces and pale green, dull lower surfaces. The inflorescences are 2 to 6-flowered and glabrous, with peduncles of 0.6–3 cm long and pedicels spreading, measuring 1.2–3 cm. The flowers are bisexual, epigynous, zygomorphic (bilaterally symmetric), resupinate, and protandrous, with a hypanthium of 0.7–1.2 cm long. The calyx is synsepalous (sepals united) with five green, firm, valvate lobes that mimic the shape and texture of the corolla, which is 4.8–6 cm long, bilabiate, and white, sometimes tinged with green or purple. The stamens are syngenesious (arrangement of stamens where their anthers are fused while their filaments are free), with white anthers that open introrsely. The ovary is inferior, featuring two carpels and two locules with large axile placentation. The fruit is a yellow or orange subglobose berry, measuring 1.7–3 cm in length and 1.8–3 cm in diameter, containing numerous tiny, dark brown or black seeds with a minutely foveate-reticulate surface, and a straight, short to spatulate dicotyledonous embryo embedded in oily endosperm. It is primarily found in montane rain forests within the Wai’anae and Ko’olau Mountains at elevations ranging from 300-850 meters.