Northeast cypripedium ( hybrid ) ( Chinese orchid book ) 

Cypripedium × ventricosum Sw. in Kongl. Vetensk. Acad. Nya Handl. 21 : 251.1800 ; cribb, Genus Cypripedium 273. pl.26, 117, 118.1997 ; chinese Orchid Encyclopedia 115. 1998. -Cypripedium macranthum Sw. var. ventricosum ( Sw. ) Rchb. f., Icon. Florae Germ. Helv. Orch. 210. 1851 ; key to Herbs in Northeast China ( Second Edition ) 895.1995.-Cypripedium manshuricum Stapf in Curtis 's Bot. Mag. 152 : sub t. 9117.1927 ; s. C. Chen et Y. Z. Xi in Proc. 12th World Orch. Conf. 144. 1987. _ Cypripedium manshuricum Stapf var. virescens Stapf. 1. c.

Plants up to 50 cm high. Stem erect, usually with 3-5 leaves. Leaf blade elliptic to ovate-elliptic, 13-20 cm long, 7-11 cm wide, glabrous or occasionally puberulent on both veins. Inflorescence terminal, usually with 2 flowers ; flowers reddish purple, pink to white, size change ; petals usually how much twist ; the lip flap is deep cystic, oval or obovate, usually with light circles around the orifice. Degenerated stamens up to 1 cm long. Flowering May-June. 

It is produced in the northwest of Heilongjiang and the Daxing 'an Mountains in the northeast of Inner Mongolia. Born under sparse forest, forest edge or grassland, altitude unknown. Russia 's Sakhalin Island ( Sakhalin Island ) and the northern part of the Korean Peninsula are also distributed. The post-selection pattern for this species is the graph in Florae Sibirica ( 1747 ) of Gmelin. 

This species is considered to be an interspecies hybrid of C. calceolus and C. macranthum. Both are distributed in Siberia and Greater Khingan Mountains and often grow in the same environment. Although the flower morphology of this hybrid is more similar to that of the big flower, it usually has 2 flowers, the petals are more or less twisted, and the ovary sometimes has glandular trichomes, which is obviously closely related to the orchid. For the discussion of this hybrid, see Cribb : The Genus Cypripedium 272-273.1997.