5. Paphiopedilum emersonii Koopowitz & P. J. Cribb, Orchid Advocate. 12(3): 86. 1986.
白花兜兰 bai hua dou lan
Paphiopedilum emersonii f. album O. Gruss & Petchleung.
Plants lithophytic. Leaves 5-7, distichous; blade abaxially pale green and with purple-red spots toward base, adaxially uniformly green or sometimes very obscurely tessellated with deep and light green, narrowly elliptic, 8-23 × 2.5-4(-5) cm, leathery, ciliate along basal margin. Scape erect, terminating in a solitary flower; peduncle green or yellowish green, 8-15 cm, white pubescent, usually with a greenish sheath at base; floral bract whitish, usually flushed with brown, elliptic, conduplicate, 2.8-3.8 cm, pubescent, ciliate; pedicel and ovary 2.5-3.5 cm, greenish white, white pubescent. Flower slightly fragrant, 8-9(-10) cm in diam.; dorsal sepal, synsepal, and petals white, sometimes flushed with pale purple-red toward adaxial base of petals; lip yellowish to whitish, with deep purple spots inside; staminode yellow or whitish yellow, with pale red-brown markings. Dorsal sepal elliptic-ovate, 3-5 × 2-3.5 cm, both surfaces puberulent, margin recurved, apex obtuse; synsepal broadly elliptic or suborbicular, 3-4.8 × 3-4.8 cm, both surfaces puberulent, apex obtuse. Petals obovate-elliptic to suborbicular, 3.5-6 × 2.5-5 cm, both surfaces sparsely puberulent, adaxially villous toward base, apex obtuse or rounded; lip subglobose or obovoid-globose, 3.5-4.5 × 2-3 cm, apical margin involute and slightly grooved along veins. Staminode trullate, appearing like a crocodile head, 15-20 × 9-10 mm, with a deep longitudinal groove centrally, obtuse at apex. Fl. Apr-Jun. 2n = 26.
Shaded cliffs or crevices of steep rocks in evergreen broad-leaved forests or thickets in limestone areas; 300-800 m. Guangxi, S Guizhou [N Vietnam].
Paphiopedilum ×glanzii O. Gruss & Perner (Orchidee (Hamburg) 57(3): 315. 2006), a natural hybrid between this species and P. micranthum, was described recently from China (without precise locality).