Description from Flora of China
Oldenlandia paridifolia (Dunn) Chun.
Herbs or subshrubs, perennial, erect, to 30 cm tall; stems green or purplish, flattened to subterete, usually sulcate along each side, glabrous. Leaves subsessile to shortly petiolate, often clustered and apparently verticillate at tops of stems; petiole to 3 mm, glabrous; blade drying papery, ovate, elliptic, or elliptic-ovate, 7-9(-12) × 2.5-4.5 cm, glabrous, base obtuse to rounded and often decurrent, apex acute or shortly acuminate; secondary veins 5-7 pairs; stipules fused to petiole bases, triangular to broadly triangular, 1-3.2 mm, glabrous, sparsely glandular-serrulate or glandular-setulose, apex with aristate projection 1-2 mm. Inflorescences terminal, capitate or subcapitate, hemispherical, 1.5-2.5 cm in diam., glabrous, subsessile; bracts triangular, 1-2 mm; pedicels to 2.5 mm. Flowers shortly pedicellate to sessile, perhaps monomorphic. Calyx glabrous; hypanthium portion purple, turbinate, ca. 1 mm, puberulent; limb lobed nearly to base; lobes on a few flowers rarely 2 or 3, elliptic, elliptic-oblong, or lanceolate (i.e., narrowed at base), 2-4 mm, obtuse to acute. Corolla white, funnelform to tubular, outside glabrous; tube 4-5 mm, inside pilosulous in upper part and throat; lobes triangular, 1-1.2 mm. Anthers exserted, ca. 1 mm. Stigma exserted, ca. 1.2 mm. Fruit indehiscent, straw-yellow, obovoid or subellipsoid, 3-3.5 × 2-2.5 mm, glabrescent; seeds numerous, black, angled, foveolate. Fl. May-Nov, fr. Apr-May.
W. C. Ko (in FRPS 71(1): 35. 1999) described the leaf blade as up to 12 cm, but this has not been seen on specimens studied and may include plants that have been subsequently separated as Hedyotis baotingensis.
● Forests or thickets at middle elevations; ca. 200 m. Hainan.