Description from Flora of China
Cypripedium macranthos Swartz var. villosum Handel-Mazzetti; C. pulchrum Ames & Schlechter; C. rubronerve Cavestro.
Plants 20-35 cm tall, with a stout, rather short rhizome. Stem erect, densely villous especially toward upper part, with several sheaths at base and 3-5 leaves above. Leaf blade elliptic or ovate-elliptic, 10-16 × 4-6.5 cm, both surfaces sparsely pubescent on veins, minutely ciliate, apex acute or shortly acuminate. Inflorescence terminal, with 1 flower; peduncle densely villous; floral bracts foliaceous, elliptic or elliptic-lanceolate, 6-8(-12) × 2-3.5 cm, both surfaces sparsely hairy, minutely ciliate, apex acuminate or shortly acuminate; pedicel and ovary 4-4.5 cm, densely villous. Flower purplish red to pink, with darker veins. Dorsal sepal elliptic-ovate or ovate, 4-5.5 × 2.5-3 cm, abaxially sparsely pubescent on veins, minutely ciliate, apex acuminate or shortly acuminate; synsepal elliptic-lanceolate, 3.5-4 × 1.5-2.5 cm, abaxially pubescent on veins, minutely ciliate, apex shallowly 2-lobed. Petals lanceolate, 5-6 × 1-1.5 cm, villous toward adaxial base, apex acuminate; lip deeply pouched, ellipsoid or subglobose, 4-5.5 × 3-4 cm. Staminode ovate-sagittate to ovate, 10-15 × 7-9 mm, abaxially slightly carinate, base auriculate, subsessile or with a very short stalk at base. Fl. May-Jul.
● Humus-rich and well-drained places in open forests, scrubby or wet grassy slopes; 1500-3700 m. Chongqing, S Gansu, W Henan, W Hubei, S Shaanxi, S Shanxi, NW Sichuan.