单花葵 dan hua kui

Herbs, annual, to 1 m tall, rarely perennial, creeping or straggling, to 90 cm tall or long, sometimes rooting at nodes, sometimes mat-forming. Stems sometimes purplish, with stipitate glandular hairs on young parts. Leaves opposite; petiole 5-27 mm; blade narrowly ovate or ovate, 1-7 × 0.5-4 cm, shortly pubescent to slightly scabridulous, 3-5-veined from base, base obtuse to attenuate, margin subentire to serrate, apex acute to acuminate. Glomerules solitary and terminal, campanulate, 8-13 × 8-30 mm, with 8-25 1-flowered capitula; subtending bracts lanceolate to obovate, 5-15 × 1-6 mm; involucre of capitula 4-5 × ca. 1 mm, stipitate glandular. Florets white or with blue tinge, 4-5 mm. Achenes brown or black, ca. 3 mm, setuliferous near apex; pappus a minute crown, pubescent; achene usually surrounded by connate phyllaries topped by scales, 2-2.5 mm.

Hong Kong [probably native to Central America; widespread throughout the tropics].