Cyanea dunbariae is a branched shrub that grows 1.5–2 meters tall. It has smooth stems and simple, alternate leaves. The leaves are ovate to broadly elliptic, measuring 10–22 cm in length and 6–14 cm in width. They have an acute to acuminate apex and an obtuse to truncate base. The leaf margins are irregularly lobed or cleft. Petioles are 4–12 cm long. The inflorescence occurs in axillary racemes with 6–8 flowers each on 30–70 mm long peduncles and 12–15 mm long pedicels. The hypanthium is ovoid, 4–6 mm long and 3–4 mm wide. They are bisexual (perfect), with a calyx that is 5-lobed and triangular lobes, 2–3 mm long, and about 1 mm wide, sometimes distinct or rarely connate. The corolla is zygomorphic (bilaterally symmetric), white with pale lilac tinges or stripes, 30–38 mm long and 3–4 mm wide, glabrous, with the tube slightly curved and lobes that are connate and spreading, nearly as long as the tube. The stamens, five in number, alternate with the corolla lobes and are connate, forming a glabrous staminal column. Anthers are glabrous, with the lower two featuring apical tufts of white hair. They open by longitudinal slits and can be coherent or form a tube for pollen release. The ovary is inferior, 2-celled, with axile placentation. The 2-lobed stigma becomes receptive after the style grows through the anther tube and releases pollen. It is found in mesic to wet forest environments at elevations ranging from 185-730 meters.