Erect or scandent herb to 2 m tall; stems puberulent, distally tomentous with short brown or purplish hairs. Leaves 4.8-12 cm long, 1.7-4.3 cm broad, broadly lanceolate, apically acuminate, basally truncate or attenuate, sometimes narrowed almost to the base of the petiole, the margin irregularly serrate or serrulate, above dark green, glandular dotted and often short pilose, beneath paler, reticulate venose, the primary and the secondary veins tomentous with brownish hairs, the lamina glabrous, dotted with sessile yellowish glands; petiole 5-15 mm long, tomentous- or villous. Inflorescence of 1-2 pairs of 2-10-flowered cymes; primary peduncles (3.5-)5-12 cm long, in vestiture resembling the stems; pedicels 0.8-4.0 cm, tomentous; bracts resembling the main leaves but smaller, subordinate bracts lacking. Flowers with the sepals 4.5-9.0 mm long, 3.5-7.0 mm broad, ovate, brownish green, both sides with yellowish hyaline glands, ciliate; corolla exter- nally glandular papillose or glandular pilose at least around the mouth, the upper lip light yellow, 6-8 mm long, 10-13 mm broad, hooded, flattened in the lateral view, the lower lip deep yellow, 15-25 mm long, 10-17 mm broad, project- ing, saccate about % of its length, internally with a tuft of white hairs below the base and between the stamens; anthers 3.5-4.0 mm long, dark brown, dehiscing throughout, the cells divaricate, equal, their distal parts bent somewhat down- ward, the filaments 1.5 mm long, glabrous; ovary glandular, style 4-5 mm long, distally decurved. Capsule 5-8 mm long, globose, with small glands and a slightly pointed apex.