Argostemma hainanicum H.S.Lo

Herbs, 10-20 cm tall; stems grayish black when dry, suberect or creeping, densely strigose-villous becoming glabrescent. Leaves opposite, anisophyllous; blade drying black adaxially, dark brown abaxially, oblong-lanceolate or oblong-ovate, 10-40 × 6-12(-15) mm, both surfaces strigose on midrib and sometimes near margins, base obtuse, margin entire or erose to ciliate, apex acute or shortly acuminate; secondary veins not visible; smaller leaf of a pair subovate, 2-8(-10) mm. Inflorescence 1-or 2-flowered, villous to glabrescent; peduncles 1-2 cm; bracts lanceolate, 1.5-2 mm. Calyx puberulent or subglabrous; lobes 5. Corolla white, rotate, glabrous; lobes 5, lanceolate, ca. 1 cm. Stamens 5; anthers coherent, dehiscent by longitudinal slits, with connective prolonged. Capsules slightly cordate, ?maybe didymous, ca. 5 × 7-8 mm, glabrous. Fl. May.