Aganosma cymosa is a liana that can grow up to 10 metres in length, pale brownish tomentose. Leaf-stalks are 1-2 cm, leaf blade broadly ovate or orbicular, 5-16 x 4-12 cm, base rounded or obtuse, apex acuminate or obtuse, rarely retuse, lateral veins 8-10 pairs. Flowers are borne in many-flowered clusters at branch ends, which are carried on stalks up to 6 cm. Bracts and bracteoles are very narrowly elliptic, 0.9-1.1 cm. Flower-stalks are about 5 mm. Calyx with several glands inside margin of sepals; sepals very narrowly elliptic, 0.9-1.1 cm, pubescent on both surfaces. Flowers are white, minutely tomentose outside, glabrous at throat; tube shorter than sepals, 6-7 mm; lobes oblong, as long as tube. Disc longer than ovary. Ovary pubescent at apex. Follicles 2, cylindric, to 30 X 0.8-1.2 cm