Shrub or suffrutescent herb, up to 1 m high, sparsely or unbranched. Stem and branches up to 0.7 cm in diam., quadrangular, winged(wings 1 mm wide); internodes up to 6 cm long. Leaves petiolate, arranged along stem; petiole 3-5 cm long; blade membranaceous, obovate, 17-31 x 7-11.5 cm, margin flat, apex acute to abruptly acuminate, base attenuate (sometimes unequal). Flowers solitary, erect; calyx green, 13 x 4 mm, lobes ovate, 11-12 x 3-5 mm, margin membranaceous, apex acute; corolla yellow, tubular to funnel-shaped, ca. 50 mm long, lobes 10 x 65-75 mm, apex acuminate; stamens barely exserted from corolla mouth, filaments 29-34 mm long, straight, anthers white, narrowly elliptic, 3-4 mm long, straight after anthesis; pollen exine reticulate; pistil ca. 38 mm long, ovary 5 x 2-2.5 mm, style ca. 32 mm, stigma lobe elliptic, 2-3 x 2-3 mm. Fruit unknown.