Description from Flora of China
Peristylus tetralobus Finet, Rev. Gén. Bot. 13: 524. 1901; Amitostigma yunnanense Schlechter; Orchis tetraloba (Finet) Schlechter; O. tetraloba var. yunnanensis (Schlechter) Soó.
Plants 7-26 cm tall. Tubers subglobose to oblong, 10-15 × 5-10 mm. Stem with 2 tubular sheaths at base, 1-leaved. Leaf cauline, porrect, linear-lanceolate, 2-8 × 0.3-0.8 cm, apex acute. Peduncle ebracteate or with 1 occasionally foliaceous sterile bract; rachis 1-3.5 cm, laxly to subdensely 3- to more than 10-flowered; floral bracts lanceolate, 3-6 mm, usually shorter than ovary, apex acute. Flowers secund, pink to pale purple; ovary and pedicel 6-9 mm. Dorsal sepal erect, oblong-ovate, concave, 2.5-3.3 × ca. 2 mm, 1-veined, apex obtuse; lateral sepals spreading to reflexed, ovate, slightly oblique, 3-4 × ca. 1.8 mm, 1-veined, apex obtuse. Petals loosely connivent with dorsal sepal and forming a hood, broadly ovate, slightly oblique, 2.8-3.5 × ca. 2 mm, 1-veined, apex obtuse; lip rhombic-obovate, 4.5-6(-8) × 3.5-4 mm, 3-lobed near middle; disk finely papillate; lateral lobes oblong-obovate, 2-3.5 × 1.6-2 mm, apex obtuse-truncate; mid-lobe oblong-obovate, 2.5-4 × ca. 2 mm, base attenuate, apex usually obtuse-truncate, or occasionally emarginate to shallowly notched to form 2 small lobules; spur ± pendulous, slightly incurved, cylindric, 3.5-6 mm, slightly dilated toward apex, apex obtuse; viscidia narrowly elliptic; stigma lobes clavate. Fl. Jun-Aug.
● Rocky soils in forests, grassy slopes; 1500-2700 m. SW Sichuan, SW and W Yunnan.