11. Cypripedium macranthos Swartz, Kongl. Vetensk. Acad. Nya Handl. 21: 251. 1800.
大花杓兰 da hua shao lan
Cypripedium macranthos f. albiflorum (Makino) Ohwi; C. macranthos var. albiflorum Makino; C. macranthos var. taiwanianum F. Maekawa; C. speciosum Rolfe; C. taiwanianum Masamune; Sacodon macranthos (Swartz) Rafinesque.
Plants 25-50 cm tall, with a stout, short rhizome. Stem erect, slightly pubescent or glabrescent, with several sheaths at base and 3 or 4 leaves above. Leaf blade elliptic or elliptic-ovate, 10-15 × 6-8 cm, slightly pubescent or glabrescent on veins on both surfaces, minutely ciliate, apex acuminate or subacute. Inflorescence terminal, 1- or rarely 2- flowered; peduncle pubescent or glabrous; floral bracts foliaceous, elliptic or rarely elliptic-lanceolate, 7-9 × 4-6 cm, both surfaces often puberulent on veins, apex shortly acuminate; pedicel and ovary 3-3.5 cm, glabrous. Flowers large, red or pink, usually with darker stripes, very rarely white. Dorsal sepal broadly ovate-elliptic or ovate-elliptic, 4-5 × 2.5-3 cm, glabrous, apex acuminate; synsepal ovate, 3-4 × 1.5-2 cm, apex shallowly 2-lobed. Petals not twisted, lanceolate, 4.5-6 × 1.5-2.5 cm, villous toward adaxial base, apex acuminate; lip deeply pouched, subglobose or ellipsoid, 4.5-5.5 cm, with a small mouth ca. 1.5 cm in diam., inner bottom hairy. Staminode ovate-oblong, 10-14 × 7-8 mm, abaxially not carinate, base sessile. Capsule narrowly ellipsoid, ca. 4 cm, glabrous. Fl. Jun-Jul, fr. Aug-Sep. 2n = 20, 21, 30.
Humus-rich soils and well-drained places in forests, forest margins, grassy slopes; 400-2400 m. Hebei, Heilongjiang, Jilin, Liaoning, Nei Mongol, Shandong, Taiwan [Japan, Korea, Russia].
Cypripedium ×ventricosum Swartz (Kongl. Vetensk. Acad. Nya Handl. 21: 251. 1800), a natural hybrid between C. macranthos and C. calceolus, was reported to be found in Heilongjiang and Nei Mongol.