Description from Flora of China
Oldenlandia acutangula (Champion ex Bentham) Kuntze.
Herbs or subshrubs, apparently biennial or perennial, erect, 25-60 cm tall; stems sometimes slightly constricted at nodes, 4-angled to 4-winged, wings to 1.5 mm wide. Leaves sessile or subsessile; blade drying stiffly papery to leathery, ovate-lanceolate, lanceolate, elliptic, or lanceolate-elliptic, 2-12 × 0.5-2.5 cm, glabrous, base cuneate to rounded, margins thickened, often inrolled, sometimes glandular-serrulate, apex acute or shortly acuminate; secondary veins indistinct; stipules fused to petiole bases, ovate or triangular, 1.5-5 mm, glabrous, margins often becoming revolute, entire or glandular-serrulate, apex acute to acuminate. Inflorescences terminal, in axils of uppermost leaves, and occasionally also axillary or pseudoaxillary at lower nodes, paniculate or corymbose, 3-20 cm, many flowered, glabrous, pedunculate; peduncle 2-8 cm; axes dichasial, sharply 4-angled to thinly 4-winged; bracts triangular to lanceolate and 0.3-5 mm, or leaflike and larger. Flowers sessile, distylous. Calyx glabrous; hypanthium portion turbinate to ellipsoid, 0.8-1 mm; limb lobed nearly to base; lobes ovate, triangular, or lanceolate, 0.8-1.2 mm. Corolla white to pink, funnelform, outside glabrous; tube 2.2-3.5 mm, inside tomentose above middle; lobes ovate-lanceolate, 2-3 mm. Anthers included or exserted, ca. 1 mm. Stigma included or exserted, 0.5-1 mm. Fruit capsular, obovoid to ellipsoid, 2-2.5 × 1-1.2 mm, glabrous, leathery, apically flat or with beak to 0.3 mm, septicidal and then loculicidal along middle of septum; seeds several, black, suborbicular, angled. Fl. May-Dec, fr. Jun-Dec.
Deb and Dutta (Taxon 34: 296-297. 1985) briefly discussed this species and formally synonymized Hedyotis elegans Wallich ex Kurz with it; however, they gave no characters or discussion of either species and gave its range as "Burma and Malaysia" even though its type is from Hong Kong, so their conclusions are provisionally not included here.
Hill slopes, open fields; near sea level to 600 m. Fujian, Guangdong, Hainan (Wanning) [N Thailand, Vietnam].