Erect or scrambling/scandent shrubby herb to 3(–5) m tall, often forming large almost impenetrable thickets and covering large areas as a “monoculture”; whole plant usually with an overpowering aromatic or foetid smell; young stems subglabrous to sericeous-puberulent with downwardly directed hairs (very rarely tomentose). Leaves with petiole of stem-leaves 2.5–10(–11.5) cm long; lamina of stem-leaves ovate to broadly cordiform, 7–21≈3–15 cm, apex acuminate to cuspidate, base subcordate to cordate with sinus to 1 cm deep, margin grossly crenate-dentate with teeth to 1(–2) cm long, sparsely sericeous-puberulent to -pubescent, usually only along midrib and main veins (rarely subglabrous). Inflorescence an open branched panicle with long spreading branches, usually also with long branches developing lateral panicles from basal nodes or upper leaf axils, (10–)15–35 cm long; flowers in lax dichasia with up to 9 flowers or solitary towards apex of panicle; bracts green, leafy, persistent, indumentum as leaves; branches and pedicels sericeous-puberulent to puberulous or densely so and with sparse to dense long capitate glands; pediels to 5(–10) mm long. Calyx puberulent to puberulous and with scattered to dense long purplish glands (rarely subsessile or absent); dorsal lobe (5–)8–21(–30 in fruit) mm long, ventral and lateral (5–)7–19(–28 in fruit) mm long; lobes linear to lanceolate, narrowly elliptic or narrowly spathulate, 0.5–2 mm wide, subacute. Corolla white to pale mauve with brown throat and one or two yellow patches on lower lip, throat with dense band of long hairs on lower lip, sparser on lateral lobes and only a few or none on dorsal lobes, 17–30(–33) mm long, cylindric part of tube 1–2(–3) mm long, throat 7–19 mm long; papillate area on lower lip of two separate elipsoid patches or fused to one; lobes all similar, broadly elliptic, 8–12(–15)≈6–10(–14) mm. Free part of filaments 2–5 mm long and fused free part ± 1 mm, glabrous or longer with scattered hairs; anthers 3–5 mm long, spur 1.5–2 mm long. Stigma ± 2 mm long, dorsal lobe absent; ovary densely hairy and glandular in apical 1/2–2/3 or all over. Capsule 15–24(–26) mm long, hairy and glandular all over or glabrous in basal half, more rarely (in Tanzania) only hairy at the very tip. Seed 4–6≈3.5–5 mm. Fig. 34, p. 224.