越南耳草 yue nan er cao

Oldenlandia chereevensis Pierre ex Pitard in Lecomte, Fl. Indo-Chine 3: 143. 1922.

Herbs, erect, perhaps perennial, to 50 cm tall; stems flattened to 4-angled, often ridged, glabrous or puberulent to hispidulous at and shortly below nodes. Leaves subsessile to petiolate; petiole to 2 mm, puberulent to hispidulous; blade drying membranous, ovate, lanceolate, or elliptic, 2-7 × 0.8-3 cm, adaxially glabrous or puberulent on principal veins, abaxially sparsely to densely puberulent or hispidulous at least on principal veins, base cuneate to rounded then decurrent, apex acute to acuminate; secondary veins 5-7 pairs; stipules fused to petiole bases, ovate-lanceolate to triangular, 3-5 mm, densely puberulent, hirtellous, or hispidulous, acuminate to aristate, marginally laciniate or with several filamentous lobes to 1 mm, often glandular at apex. Inflorescences terminal and sometimes in axils of uppermost leaves, cymose to paniculate, 3-7 cm, several to many flowered, glabrous, usually slender, pedunculate; peduncles 1-2 cm; bracts lanceolate, 0.8-1 mm; pedicels 6-10 mm. Flowers all pedicellate. Calyx glabrous; hypanthium portion obconical, 0.5-0.8 mm; limb lobed essentially to base; lobes triangular, 0.1-0.3 mm. Corolla white, tubular to rotate, outside glabrous; tube 0.5-1 mm, inside apparently glabrous; lobes oblong-lanceolate, ca. 0.5 mm. Anthers exserted, ca. 0.5 mm. Stigma apparently exserted, ca. 0.2 mm. Fruit capsular, obconical, turbinate, or subglobose, often somewhat didymous, 1.5-2 × 1-1.5 mm, glabrous, loculicidally dehiscent across top, beak rounded, ca. 0.4 mm high; seeds ca. 10, dark brown, angled. Fl. May-Jul.

On damp humus soil in forests; [below 100-1300 m in Thailand]. Hainan [Cambodia, Thailand, Vietnam].

The name Hedyotis chereevensis has been attributed to W. C. Ko (Fl. Hainan. 3: 306, 579. 1974), but this appears to be a later, superfluous combination.