Shrubby herb or soft-wooded shrub to 2.5(–3) m tall, sometimes with stilt-roots; young stems quadrangular and longitudinally furrowed, subglabrous to densely sericeous with closely appressed often (if sparse) almost invisible hairs. Leaves with petiole (1–)2–6.5 cm long on larger leaves with sparse to dense long spreading hairs on edges; lamina ovate to elliptic, largest 8–24≈3.5–9.5 cm, apex acuminate to cuspidate, base attenuate, beneath subglabrous to pubescent with broad glossy hairs along midrib and veins, sparser (rarely dense) on lamina, above with sparse to dense long broad appressed hairs all over, denser on midrib (rarely glabrous). Flowers in dense capitate racemoid heads or elongated racemes to 3 cm long; peduncle 0.5–23 mm long, winged, glabrous to sericeous; bracts often purplish; pedicels to 1 mm long; bracteoles linear to spathulate, 5–14(–18) mm long, sometimes with apical part recurved, conspicuously whitish sericeous-pubescent (more rarely sparsely purplish-sericeous-pubescent on midrib and margins) on edges (rarely also with stalked capitate glands). Calyx 5–10 mm long, usually conspicuously whitish sericeous-pubescent or densely so apically, more rarely sparsely sericeous in apical half with purple appressed hairs, glabrous towards base (rarely also with stalked capitate glands), lobes linear-lanceolate or slightly spathulate, acute to obtuse. Corolla pure white (rarely) or white with pink to purple lines in throat, pubescent with broad glossy hairs, densest dorsally and sometimes only in a dorsal band; tube below attachment of stamens 8–15 mm long, throat 10–25 mm long and 8–20 mm in diameter apically, lobes 4–8 mm long, acute or bifid at apex. Free part of filaments 4–8 and 6–12 mm long, densely hairy in lower half; anthers 2–3 mm long; ventral stigma lobe 2–3 mm long. Capsule 11–14 mm long. Seed ellipsoid to circular, 4–5≈3–4 mm. Fig. 33, p. 216.