A stiffly erect plant up to 1 metre tall and covered with fine hairs. The flowers are scentless, are 25 mm to 50 mm across and are produced in the summer months. Each petal bears 2 or 3 discontinous black lines. The five narrow pointed sepals exceed the petals and are joined at the base to form a rigid tube with 10 ribs. Leaves are pale green, opposite, narrowly lanceolate, held nearly erect against stem and are 45 mm to 145 mm long. Seeds are produced in a many-seeded capsule.