Description from Flora of China
Orchis dentata Swartz, Kongl. Vetensk. Acad. Nya Handl. 21: 207. 1800; Habenaria dentata var. tohoensis (Hayata) S. S. Ying; H. geniculata D. Don; H. miersiana Champion ex Bentham; H. tohoensis Hayata; Plantaginorchis dentata (Swartz) Szlachetko; Platanthera dentata (Swartz) Lindley; P. geniculata (D. Don) Lindley.
Plants 35-87 cm tall. Tubers oblong-ovoid to oblong, 2-5 × 1-3 cm, fleshy. Stem erect, terete, stout, loosely with 3-5 leaves and several bractlike leaflets. Leaf blade oblong to narrowly elliptic, 5-15 × 1.5-4 cm, base amplexicaul, margin white when dried, apex acute or acuminate. Raceme often many flowered, 5-12 cm; floral bracts lanceolate, 2-3 cm, basal ones ca. as long as ovary, apex acuminate; ovary twisted, terete, including pedicel 2-3 cm. Flowers white. Sepals and petals ciliate; dorsal sepal forming a hood with petals, erect, broadly ovate, concave, 10-13 × 7-8 mm, 5-veined, apex acute; lateral sepals spreading or reflexed, obliquely ovate, 14-16 mm, 5-veined, apex acute. Petals falcate-lanceolate, 8-9 × 2-2.5 mm, 2-veined, unlobed; lip broadly obovate, 15-18 × 12-16 mm, 3-lobed; lateral lobes subrhombic or flabellate, 7-8 mm wide, apical margin serrate; mid-lobe linear-lanceolate or ligulate-lanceolate, 5-7 × 1.5-3 mm, 3-veined, apex obtuse; spur pendulous, green below middle, cylindric-clavate, 3.5-4 cm, longer than ovary, somewhat geniculate in basal half, slightly curved, gradually dilated toward end, apex obtuse, with conspicuously raised structure surrounding mouth; stigmas oblong. Fl. Aug-Oct. 2n = 64.
Forests on slopes or along valleys; 200-2300 m. Anhui, N Fujian, Guangdong, Guangxi, Guizhou, Hubei, Hunan, Jiangxi, Sichuan, Taiwan, Xizang, Yunnan, Zhejiang [Cambodia, India, Japan, Laos, Myanmar, Nepal, Thailand, Vietnam].