Clermontia samuelii, a member of the Campanulaceae (bellflower) family, is a terrestrial shrub 1.2 to 5 m (4 to 16 ft) tall. The leaves are elliptical, sometimes broader at the tip, with blades 5 to 10 cm (2 to 4 in) long and 1.8 to 4.5 cm (0.7 to 1.8 in) wide. The upper surfaces of the leaves are dark green, often tinged purplish, and may be sparsely hairy. The lower surfaces of the leaves are pale green, and sparsely to densely hairy. The leaf margins are thickened, with shallow, ascending, rounded teeth. The tips and bases of the leaves are typically sharply pointed. The inflorescences bear two to five flowers on a main stem that is 4 to 18 mm (0.2 to 0.7 in) long. The stalk of each individual flower is 12 to 28 mm (0.5 to 1.1 in) long. The hypanthium (cup-like structure at the base of the flower) is widest on the top, 8 to 14 mm (0.3 to 0.6 in) long, and 5 to 10 mm (0.2 to 0.4 in) wide. The sepals and petals are similar in color (rose or greenish white to white), curved, and tubular. The flowers are 36 to 55 mm (1.4 to 2.2 in) long and 5 to 10 mm (0.2 to 0.4 in) wide. The lobes of the sepals and petals are erect and extend 0.2 to 0.5 times beyond the tube.