有翅蛇根草 you chi she gen cao

Herbs, ascending, to 1 m tall; stems drying compressed, glabrous or puberulent. Leaves in subequal pairs; petiole 1-3 cm, subglabrous; blade drying submembranous, grayish green adaxially, pale abaxially, ovate, elliptic, or lanceolate-ovate, 7-13 × 3-5.5 cm, glabrous on both surfaces, base subcuneate and sometimes shortly decurrent, margins undulate, apex subacuminate; secondary veins 8-10 pairs; stipules caducous, not seen. Inflorescence many flowered, pubescent; peduncle 1.5-5 cm; axes helicoid, usually shorter than 1 cm; bracts reduced or absent. Flowers distylous, with pedicels ca. 2.5 mm. Calyx pubescent; hypanthium portion turbinate-campanulate, ca. 1.8 mm, 5-ribbed; lobes subtriangular, ca. 0.7 mm. Corolla white, tubular with swollen base, subglabrous outside; tube ca. 12 mm, with white villous ring in throat; lobes triangular to broadly ovate, ca. 1.5 mm, dorsally winged and with short horn at apex. Capsules ca. 2.5 × 6 mm. Fl. Apr-May.

Dense forests; 500-700 m. Yunnan [Thailand].

H. S. Lo (in FRPS 71(1): 173. 1999) described this species as distylous but described only an apparently short-styled flower.