Aganosma cymosa is a liana that can grow up to 10 m (33 ft) in length, pale brownish tomentose. Leaf-stalks are 1–2 cm (0.4–0.8 in), leaf blade broadly ovate or orbicular, 5–16 cm (2.0–6.3 in) by 4–12 cm (1.6–4.7 in), base rounded or obtuse, apex acuminate or obtuse, rarely retuse, lateral veins eight to ten pairs. Flowers are borne in many-flowered clusters at branch ends, which are carried on stalks up to 6 cm (2.4 in). Bracts and bracteoles are very narrowly elliptic, about 1 cm (0.4 in) long. Flower-stalks are about 5 mm (0.2 in). Calyx with several glands inside margin of sepals; sepals very narrowly elliptic, about 1 cm (0.4 in), pubescent on both surfaces. Flowers are white, minutely tomentose outside, glabrous at throat; tube shorter than sepals, 6–7 mm (0.2–0.3 in); lobes oblong,