Description from Flora of China
Hyptis decurrens (Blanco) Epling; Pycnanthemum decurrens Blanco.
Herbs annual, robust, erect. Stems 0.5-1.5 m, finely striate, scabrid, angles pubescent. Petiole 1-3.5 cm; leaf blade lanceolate, 8-18 × 1.5-4 cm, adaxially sparsely minute hispid, abaxially densely glandular, pilose on veins, base attenuate, margin obtuse serrate, apex attenuate. Flowers numerous, in axillary globose capitula ca. 1.5 cm in diam.; peduncle 1-10 cm; bracts numerous, appressed, lanceolate to linear, longer than capitulum, entire, densely pilose. Calyx green, ca. 4 × 2 mm, minutely hispid, base villous; teeth subulate, ca. 2.2 mm; fruiting calyx tubular-dilated, to 10 × ca. 3.2 mm. Corolla cream-white, ca. 6 mm, puberulent; tube ca. 1 mm wide at base, throat slightly wider; upper lip 1-1.2 mm, lobes ovate, reflexed; lower lip ca. 2.5 × as long as upper, middle lobe concave, clawed at base; lateral lobes smaller, triangular. Nutlets chestnut brown, oblong, adaxially ribbed, ca. 1.2 × 0.6 mm, with 2 basal white scars.
Open waste areas. Guangdong, Guangxi, Taiwan [native in tropical America, widespread tropical weed].