47. Ophiorrhiza nutans C. B. Clarke ex J. D. Hooker, Fl. Brit. India. 3: 84. 1880.
垂花蛇根草 chui hua she gen cao
Herbs, weak to erect, to 70 cm tall; stems densely reddish brown villous with multicellular trichomes. Leaves in subequal to unequal pairs; petiole 0.5-2 cm, densely pubescent; blade drying papery, ovate, lanceolate, elliptic, or elliptic-oblong, 3-8(-13) × 1.5-4 cm, sparsely pilose or strigose adaxially, glabrescent except pubescent along principal veins abaxially, base obtuse to subrounded then attenuate, margins ciliolate, entire or undulate, apex acute to cuspidate; secondary veins 9-13[-15] pairs; stipules persistent, lanceolate or subovate, 8-10 mm, acuminate to 2-lobed. Inflorescence congested-cymose to corymbiform, many flowered, densely hirtellous; peduncle 1-3[-6] cm; bracts linear-oblong or lanceolate, 5-10 mm, ciliate, sometimes fimbriate and/or with a linear lobe at each side. Flowers distylous, subsessile. Calyx densely hispidulous to glabrescent; hypanthium subturbinate, ca. 1.5 mm; lobes sublanceolate, ca. 1.2 mm. Corolla white, tubular-funnelform, glabrous or sparsely hispid outside; tube [6.5-]9[-19] mm, inside sparsely pilosulous near middle and barbate in throat; lobes subtriangular or subovate, 2-3 mm, dorsally narrowly winged. Capsules mitriform, ca. 2.5 × 6-7 mm, hispidulous to subglabrous.
Moist forests; 700-2400 m. Xizang (Mêdog), Yunnan [NE India, Myanmar, Nepal].
Measurements in brackets are taken from the description of this species by Deb and Mondal (Bull. Bot. Surv. India 39(1-4): 82. 1997) and may be expected in Chinese plants. H. S. Lo (in FRPS 71(1): 131. 1999) and Deb and Mondal noted that this species is distylous, with the corollas similar in size in both floral forms and the stigmas and anthers reciprocally placed in the corolla throat and near the base of the corolla tube, respectively. H. S. Lo described the corolla tubes as ca. 9 mm; the Fl. Bhutan (2(2): 779. 1999) described them as 6.5-8.5 mm; and Deb and Mondal described them as 13-19 mm.
Ophiorrhiza hainanensis was synonymized with O. nutans by Duan and Lin (Acta Phytotax. Sin. 45: 877. 2007). However, several distinctions between these were cited by H. S. Lo (Bull. Bot. Res., Harbin 10(2): 30. 1990), and these species are provisionally separated here pending further study.