Description from Flora of China
Cypripedium concolor Bateman, Bot. Mag. 91: ad t. 5513. 1865; Cordula concolor (Lindley ex Bateman) Rolfe; Paphiopedilum concolor var. dahuaense Z. J. Liu & J. Yong Zhang; P. concolor var. immaculatum Z. J. Liu & J. Yong Zhang; P. wenshanense Z. J. Liu & J. Yong Zhang f. album O. Gruss & Petchleung.
Plants lithophytic or terrestrial. Leaves 4-6, distichous; blade abaxially purple or densely marked with purple speckles, adaxially tessellated with dark and whitish or light green, oblong or oblong-elliptic, 7-21 × 3.5-5.5(-7.5) cm, leathery, rounded and minutely bilobulate at apex. Scape suberect or arching, terminating in 1 or 2(or 3) flowers; peduncle green, heavily spotted purple, 5-7(-8) cm, densely white pubescent; floral bract green, ovate, conduplicate, 1-3(-4) × 1-2 cm, abaxially with purple speckles and along midvein hairy, ciliate; pedicel and ovary 3-4.5 cm, densely white pubescent. Flowers slightly scented, 5-7 cm in diam., usually yellowish to ivory-white ± finely spotted with purple or brown-purple throughout. Dorsal sepal broadly ovate, 2.5-4.2 × 2.4-4.4 cm, abaxially slightly puberulent on midvein, ciliate, apex obtuse to retuse; synsepal similar to dorsal sepal, slightly smaller. Petals obliquely elliptic to rhombic-elliptic, 3-5 × 1.8-3.1 cm, both surfaces very minutely puberulent, ciliate, rounded at apex; lip ellipsoid to ovoid, 3.5-4.5 cm; pouch 2.2-3 × 1.4-1.7 cm, outside very minutely puberulent, apical margin incurved. Staminode ovate to ovate-triangular, 10-12 × 8-11 mm, basal margin sometimes minutely ciliate. Fl. May-Aug. 2n = 26.
Paphiopedilum concolor is a widespread species very variable in leaf markings and floral morphology and coloring. Based on these variations, many varieties were described recently, including P. concolor var. dahuaense and P. concolor var. immaculatum from Guangxi (Acta Bot. Yunnan. 22: 393. 2000). Paphiopedilum wenshanense f. album (Orchidee (Hamburg) 53: 383. 2002) seems to be the same taxon as P. concolor var. dahuaense.
Crevices of shaded cliffs or rocky and well-drained places in limestone areas; 300-1400 m. W Guangxi, S Guizhou, S Yunnan [Cambodia, Laos, Myanmar, Thailand, Vietnam].